Method of recording and reproduction of information using a recording medium available for information overlap recording, a recording medium and a recording and reproducing apparatus using the method

Claim 3

A method according to claim 1, wherein the first information and the second information have different recording densities or modulation modes.

Claim 4

A method according to claim 1, wherein the first information includes a linguistic dictionary, and the second information includes at least one of words, underlines and translated words needed by a user.

Claim 5

A method according to claim 1, wherein the first information includes video information, and the second information includes audio information.

Claim 8

An information recording medium comprising: a transparent substrate having first information prerecorded in the form of pit strings of a phase structure on at least one track on at least one surface of the substrate; and an opto-magnetic recording film deposited directly on the at least one surface of the substrate, the opto-magnetic recording film being responsive to application of a magnetic field having polarities corresponding to second information to be recorded in the presence of a high-power radiation beam emitted onto the recording medium for enabling recording of the second information in at least partially overlapping relation with the first information on the at least one track; wherein the first information is pre-recorded on a first part of the substrate, and a second part of the substrate having no first information recorded thereon and provided with the opto-magnetic recording film enables recording of third information related to the first or second information thereon; and wherein the first information is reproduced in accordance with changes of intensity of a reflected light of the high-power radiation beam from the information recording medium simultaneously with the overlap-recording of the second information.

Claim 9

An information recording medium comprising: a transparent substrate having first information prerecorded in the form of pit strings of a phase structure on at least one track on at least one surface of the substrate; and an opto-magnetic recording film deposited directly on the at least one surface of the substrate, the opto-magnetic recording film being responsive to application of a magnetic field having polarities corresponding to second information to be recorded in the presence of a high-power radiation beam emitted onto the recording medium for enabling recording of the second information in at least partially overlapping relation with the first information on the at least one track; wherein the first information is pre-recorded on a first part of the substrate, and a second part of the substrate having no first information recorded thereon and provided with the opto-magnetic recording film enables recording of third information related to the first or second information thereon; and wherein the first information is reproduced in accordance with changes of intensity of a reflected light of the high-power radiation beam from the information recording medium simultaneously with the overlap-recording of the second information.

Claim 10

An information recording medium according to claim 6, wherein the substrate has a shape of a circular disc.

Claim 11

An information recording medium according to claim 6, wherein the substrate has a shape of a card.

Claim 12

An information recording medium according to claim 6, wherein a first index area for the first information is formed as a pit string of a phase structure, and a second index area for the second information is formed on the opto-magnetic recording film, the first and second index areas being located so that the first and second index areas at least partially overlap.

Claim 13

An information recording medium according to claim 9, wherein a record recorded in the second index area includes information representing the content of the second information recorded by opto-magnetic recording on the opto-magnetic ring film and information representing correspondence between the first information and the second information.

Claim 14

An information recording medium according to claim 6, wherein a first index area for the first information is formed as a pit string of a phase structure, and a second index area for the second information is formed on the opto-magnetic recording film, the first and second index area being spaced from one another.

Claim 15

An information recording medium according to claim 11, wherein a record recorded in the second index area includes information representing the content of the second information recorded by opto-magnetic recording on the opto-magnetic recording film and information representing the correspondence between the first information and the second information.

Claim 16

An information recording medium according to claim 1, wherein the first information includes a linguistic dictionary, and the second information includes at least one of words, underlines and translated words needed by a user.

Claim 17

An information recording medium according to claim 6, wherein the first information includes video information, and the second information includes audio information.

Claim 18

A method according to claim 6, wherein the second information is information reproduced simultaneously with reproduction of the first information.

Claim 19

A method according to claim 6, wherein the second information is control information of the first information.

Claim 20

A method according to claim 6, wherein the second information is information indicative of a position on the information recording medium at which information related to the first information is recorded.

Claim 21

A recording and reproducing apparatus comprising: an information recording medium including a transparent substrate having first information pre-recorded in the form of pit strings of a phase structure on at least one track on at least one surface of the substrate, and an opto-magnetic recording film formed on the at least one surface of the substrate, the opto-magnetic recording film being responsive to application thereof of a magnetic field having polarities corresponding to second information to be recorded in the presence of a high-power radiation beam emitted onto the recording medium for enabling overlap-recording of the second information on the at least one track having the first information pre-recorded thereon; irradiation means for emitting the high-power radiation beam onto the information recording medium during recording of the second information and for emitting a low-power radiation beam onto the information recording medium during an operation other than the recording of the second information; magnetic field application means for applying the magnetic field having polarities corresponding to the second information during recording of the second information; first reproduction means for reproducing the first information in accordance with changes of intensity of a reflected light from the information recording medium; and second reproduction means for reproducing the second information from a rotation of a polarization plane of the reflected light from the information recording medium, the second reproduction means including a variable gain amplifier, the gain of the variable gain amplifier being varied in accordance with an amount of a signal from the first reproduction means; wherein the gain of the variable gain amplifier varies in inverse proportion to the amount of the signal from the first reproduction means corresponding to the first information.

Claim 22

A recording and reproducing apparatus comprising: an information recording medium including a transparent substrate having first information pre-recorded in the form of pit strings of a phase structure on at least one track on at least one surface of the substrate, and an opto-magnetic recording film formed on the at least one surface of the substrate, the opto-magnetic recording film being responsive to application thereof of a magnetic field having polarities corresponding to second information to be recorded in the presence of a high-power radiation beam emitted onto the recording medium for enabling overlap-recording of the second information on the at least one track having the first information pre-recorded thereon; irradiation means for emitting the high-power radiation beam onto the information recording medium during recording of the second information and for emitting a low-power radiation beam onto the information recording medium during an operation other than the recording of the second information; magnetic field application means for applying the magnetic field having polarities corresponding to the second information during recording of the second information; first reproduction means for reproducing the first information in accordance with changes of intensity of a reflected light from the information recording medium; and second reproduction means for reproducing the second information from a rotation of a polarization plane of the reflected light from the information recording medium, the second reproduction means including a variable gain amplifier, the gain of the variable gain amplifier being varied in accordance with an amount of a signal from the first reproduction means; wherein the gain of the variable gain amplifier varies in inverse proportion to the amount of the signal from the first reproduction means corresponding to the first information.