JP4950120B2 - Optical recording medium recording method, recording medium manufacturing method for recording information, and optical recording medium recording apparatus - Google Patents

Description

The present invention relates to an optical recording medium recording method , a recording medium manufacturing method on which information is recorded, and an optical recording medium recording apparatus.

  Optical recording media such as DVD-R and Blu-ray (registered trademark) discs employ a method of recording information in two layers in order to increase the recording capacity. In recent years, a recording method using a two-photon absorption compound has been studied in order to perform recording on more layers.

  A two-photon absorption compound is a compound that absorbs light and excites electrons only when two photons enter at the same time. Therefore, the two-photon absorption compound has a characteristic that the reaction occurs in proportion to the square of the intensity of light and the position selectivity in the depth direction is high. More specifically, when the laser beam is focused and irradiated, the two-photon absorption compound absorbs light only in the vicinity of the focal point, and no reaction occurs at a position away in the depth direction (optical axis direction). Therefore, the two-photon absorption compound can cause a reaction in a narrow region in the depth direction, and a recording layer made of this compound is suitable for multi-layer recording.

  In a multilayer recording type optical recording medium using a conventional two-photon absorption compound, an intermediate layer is provided between recording layers. For example, the recording layer has a thickness of 0.01 to 0.5 μm, and the intermediate layer has a thickness of 0.1 to 5 μm (Patent Document 1). The thickness of the intermediate layer is sufficient to prevent the occurrence of interlayer crosstalk. The thickness of the recording layer is the reflection intensity at the interface between the recording layer and the intermediate layer, and sufficient modulation is obtained. It was as thick as possible. The reflection at the interface will be described in detail. In an unrecorded state, the reflected light at the interface below the recording layer (the side on which the laser beam for recording or reproduction is incident is on the upper side) and the upper side The reflected light is weakened by using an optical path difference with the reflected light at the interface and setting the two reflected lights to interfere and weaken each other. After recording, by changing the refractive index of the recording layer, the optical path length of the reflected light from the lower side of the recording layer is changed, and interference between the light reflected by the upper interface and the light reflected by the lower interface is reduced. As a result, a stronger light was returned than in the case of no recording.

  Therefore, conventionally, a thin recording layer of a nanometer level that can adjust the degree of interference between the reflected light of the upper interface and the reflected light of the lower interface has been used.

JP 2008-074708 A

  However, since the optical recording medium as described above can record only one layer of information on one recording layer, recording layers for the number of layers to be recorded are required for multi-layer recording, which increases the number of manufacturing steps. there were.

  The present invention has been made in view of the above-described background, and an object of the present invention is to perform recording of more layers in one recording layer and to simplify the manufacturing process of the optical recording medium.

The present invention that solves the above-described problems includes a recording layer having a two-photon absorption compound capable of changing a refractive index by exposure, a first adjacent layer adjacent to one side of the recording layer, and the recording layer. A method of recording an optical recording medium comprising a second adjacent layer adjacent to the other side, wherein the laser light is focused on a region adjacent to the first interface with the first adjacent layer of the recording layer And changing the refractive index of only the adjacent region , forming a pit using the change in reflectance of the first interface, and recording information on the first layer in the recording layer; Of the recording layer, the region adjacent to the second interface with the second adjacent layer is irradiated with focused laser light to change the refractive index of only the adjacent region, and the reflectance of the second interface is changed. by utilizing a change to form a pit to record information to the second layer in the recording layer Characterized by a step.

  According to such a method, the information of the first layer can be recorded using the change in reflectance of the first interface between the recording layer and the first adjacent layer, and the recording layer and the second adjacent layer can be recorded. The information on the second layer can be recorded using the change in the reflectance of the second interface between the first and second layers. That is, since two layers can be recorded on one recording layer, compared with a recording medium using a conventional two-photon absorption compound, the number of information recording layers is the same (here, “ This means not the number of “recording layers” but the number of layers in which information is recorded. Hereinafter, the layers in this sense are referred to as “information recording layers”). If there is. Therefore, it is possible to simplify the manufacturing process of the optical recording medium.

  In the above method, the optical recording medium has a plurality of recording layers and an intermediate layer sandwiching each recording layer, and the intermediate layer is the first adjacent layer or the second adjacent layer. There may be a certain configuration. That is, there may be a case where there are a plurality of recording layers.

  An optical recording medium recorded by such a method includes a plurality of recording layers having a two-photon absorption compound whose refractive index can be changed by exposure, an intermediate layer sandwiching each of the plurality of recording layers, A recording layer and a substrate that supports the intermediate layer, wherein the thickness of the recording layer is larger than a range in which a two-photon absorption reaction occurs, and is adjacent to an interface between the recording layer and the adjacent intermediate layer The refractive index of only the area to be changed by exposure causes a change in reflectance due to the difference in refractive index at the interface between the intermediate layer and the recording layer, and information is stored in two layers within one recording layer. It is recorded.

  That is, in the conventional multilayer recording optical recording medium using the two-photon absorption compound, the recording layer is provided with a recording layer having a thickness smaller than the range in which the two-photon absorption reaction occurs. In the medium, in order to record two layers of information in one recording layer, the thickness of the recording layer is made larger than the range in which the two-photon absorption reaction occurs.

In such a medium, in order to provide as many recording layers as possible, both the recording layer and the intermediate layer should be thin as long as interlayer crosstalk does not occur. Therefore, both layers have the same thickness. It is good to do. For example, the thickness of the recording layer is preferably 0.5 to 2 times the thickness of the intermediate layer.
The thickness of the recording layer is preferably 1 μm or more in order to prevent interlayer crosstalk, and 20 μm or less in order to improve the recording density in the depth direction.

The present invention for solving the above-described problems provides a method for manufacturing a recording medium on which information is recorded, using the above-described method. That is, a recording layer having a two-photon absorption compound whose refractive index can be changed by exposure, a first adjacent layer adjacent to one side of the recording layer, and a second adjacent adjacent to the other side of the recording layer An optical recording medium on which information is recorded, wherein a focused laser beam is irradiated on a region of the recording layer adjacent to the first interface with the first adjacent layer. Changing the refractive index of only the adjacent region , forming a pit using the change in reflectance of the first interface, and recording information in the first layer in the recording layer; Among them, the laser beam condensed to the region adjacent to the second interface with the second adjacent layer is irradiated to change the refractive index of only the adjacent region, and the change in the reflectance of the second interface is used. a step of to form a pit recording information on the second layer in the recording layer , Characterized by having a.

The apparatus of the present invention that solves the above-described problem includes a recording layer having a two-photon absorption compound capable of changing a refractive index by exposure, a first adjacent layer adjacent to one side of the recording layer, An optical recording medium recording apparatus comprising a second adjacent layer adjacent to the other side of the recording layer, a laser light source that emits laser light, and an optical system that condenses the laser light emitted from the laser light source, A focus actuator that adjusts the focus position of the laser beam by moving the optical system, and at least one of the laser beam and the optical recording medium is moved relatively to thereby irradiate the optical recording medium with the laser beam. And a control device that controls the scanning device and the focus actuator. The control device includes the scanning device and the focus actuator. The eta is controlled to irradiate a focused laser beam to a region adjacent to the first interface with the first adjacent layer in the recording layer to change the refractive index of only the adjacent region. A pit is formed using a change in reflectance at the interface of 1 and information is recorded in the first layer in the recording layer, and adjacent to the second interface of the recording layer with the second adjacent layer By irradiating the region with the focused laser beam, the refractive index of only the adjacent region is changed, pits are formed using the change in the reflectance of the second interface, and information is recorded on the second layer in the recording layer. Is recorded.

  According to such a manufacturing method and apparatus, similarly to the recording method described above, since two layers can be recorded on one recording layer, the same information recording can be performed as compared with a recording medium using a conventional two-photon absorption compound. For the number of layers, half the number of recording layers is sufficient. Therefore, it is possible to simplify the manufacturing process of the optical recording medium.

  In such a device, the control device controls the scanning device and the focus actuator to focus the laser beam on the first interface or the second interface in a region where information is not recorded. It is desirable to record information in a layer in a region adjacent to the interface.

  By performing focusing in an area where information is not recorded in this way, the amount of reflected light is stabilized, so that stable focusing can be performed. It should be noted that the area where information is not recorded here refers to both areas that can be recorded, but that are not yet recorded, and that are not scheduled to be recorded as the specifications of the recording medium. means.

  As described above, according to the recording method of an optical recording medium, the optical recording medium, the method of manufacturing the recording medium on which information is recorded, and the recording apparatus of the optical recording medium of the present invention, two recording layers of the optical recording medium are used. Since information can be recorded in the layer, the number of layers of the optical recording medium can be reduced as compared with the conventional optical recording medium using the two-photon absorption compound, and the manufacturing process can be simplified.

  Next, an optical recording disk recording apparatus and a recording method (manufacturing method) using the same according to an embodiment of the present invention will be described. FIG. 1 is a diagram showing a schematic configuration of an optical recording disk recording apparatus (hereinafter referred to as “optical recording disk drive”) according to an embodiment, and FIG. 2 is an enlarged cross-sectional view of the optical recording disk. 3 is an enlarged view of the optical pickup, FIG. 4 is a block diagram of the control device, and FIG. 5 is an enlarged cross-sectional view of the optical recording disk for explaining the positions of pits recorded on the optical recording disk. FIG.

  As shown in FIG. 1, an optical recording disk drive 1 is an apparatus for optically recording information (data) input from a computer (PC) or the like on an optical recording disk 10, and mainly supports the optical recording disk 10. A spindle 31 that rotates, a motor 32 that rotates the spindle 31, an optical pickup 20, a guide 33 that guides the optical pickup 20 to move in the radial direction of the optical recording disk 10, and a control device 100.

  As shown in FIG. 2, an optical recording disk 10 as an example of an optical recording medium has a plurality of intermediate layers 12 on a substrate 11 so that a recording layer 13 is sandwiched between the intermediate layers 12. Is provided. A cover layer 14 is provided on the uppermost intermediate layer 12.

  The substrate 11 is a plate for supporting the intermediate layer 12 and the recording layer 13, and is made of a resin plate, a glass plate, a metal plate, a semiconductor plate, or the like.

  The intermediate layer 12 is an example of a first adjacent layer and a second adjacent layer, and maintains an interval between the recording layers 13 and is adjacent to the recording layer 13 to form an interface with the recording layer 13. It enables reflection of light at the interface.

  The thickness of the intermediate layer 12 is large enough to prevent interlayer crosstalk from occurring between the information recording layers 15 and 16 above and below the single intermediate layer 12. From this viewpoint, the thickness of the intermediate layer 12 is, for example, 1 μm or more, desirably 5 μm or more, and more desirably 10 μm or more. Further, since the increase in the thickness of the intermediate layer 12 causes an increase in the thickness of the entire medium and is a limiting factor when increasing the number of layers, from this viewpoint, the thickness of the intermediate layer 12 is 20 μm or less. The thickness is desirably 10 μm or less, and more desirably 5 μm or less.

  The recording layer 13 is a layer containing a two-photon absorption compound. A two-photon absorption compound is a compound that absorbs light by excitation of electrons only when two photons enter within a very short time interval. When used as an optical recording medium as in the present invention, it is possible to cause a chemical reaction using the excitation energy of the electrons, thereby modulating the refractive index and absorption rate of light (light used for reproduction light). Compound is used. For example, diallyl ethene can be used as the two-photon absorption compound.

  As shown in FIG. 5, the thickness of the recording layer 13 is such that the information recording layer 15 is recorded in a region adjacent to the interface (first interface) with the upper intermediate layer 12 of one recording layer 13, It has a sufficient size such that interlayer crosstalk does not occur between the information recording layer 16 recorded in an area adjacent to the interface (second interface) with the intermediate layer 12 on the side. That is, the thickness of the recording layer 13 is larger than the size of the range where the two-photon absorption reaction occurs. From this viewpoint, the thickness of the recording layer 13 is, for example, 1 μm or more, desirably 5 μm or more, and more desirably 10 μm or more. Further, since the increase in the thickness of the recording layer 13 causes an increase in the thickness of the entire medium and is a limiting factor when increasing the number of layers, from this viewpoint, the thickness of the recording layer 13 is 20 μm or less. The thickness is desirably 10 μm or less, and more desirably 5 μm or less.

  The cover layer 14 is a layer that protects the intermediate layer 12 and the recording layer 13, and any material can be used as long as it can transmit laser light during recording and reproduction. For example, resin or glass can be used. Furthermore, if the recording layer 13 is a material that can selectively block short-wave light that causes a one-photon absorption reaction, the recording layer 13 can be prevented from being deteriorated by natural light.

  In addition to the above layers, the optical recording disk 10 may be provided with other layers such as an antireflection film and a short wave light blocking film.

  On the other hand, as shown in FIG. 3, the optical pickup 20 includes a lens barrel 21, a laser 22 serving as a laser light source, a beam splitter 23, a collimator lens 24, a shutter 25, an objective lens 27, a first light receiver 28, and a second light receiver. A container 29 is provided.

  The laser 22 is a pulse laser that emits light intermittently. Preferably, a femtosecond laser light source that emits strong laser light within an extremely short time is used in order to efficiently cause a two-photon absorption reaction. The laser 22 may be a continuous wave laser, and the laser oscillation medium is not particularly limited as long as the two-photon absorption reaction of the recording layer 13 can be caused.

  The beam splitter 23 is composed of a half mirror or the like, and is disposed on the downstream side of the optical path of the pulse laser beam emitted from the laser 22. The beam splitter 23 branches a part of the laser emitted from the laser 22 to the first light receiver 28, and branches a part of the light returned from the optical recording disk 10 to the second light receiver 29.

  The collimating lens 24 is a lens that is disposed on the downstream side of the optical path of the pulsed laser light emitted from the laser 22 with respect to the beam splitter 23 and converts the pulsed laser light into a parallel light beam.

  The shutter 25 is an element that allows pulse laser light to pass (on) or shut off (off), and includes a deflection element 25a and a shutter plate 25b having an opening 25c. The shutter 25 is disposed on the downstream side of the optical path of the pulsed laser light emitted from the laser 22 with respect to the collimating lens 24. The shutter 25 may be a non-mechanical optical switch for high speed operation. The deflection element 25a is composed of an electro-optic modulation element (EOM), and has a refractive index that changes according to an input signal. When no signal is input to the deflection element 25a, the pulse laser beam passes through the opening 25c. When a signal is input, the pulse laser beam is bent, and the pulse laser beam is blocked by the shutter plate 25b.

  The objective lens 27 is disposed on the downstream side of the optical path of the pulsed laser light emitted from the laser 22 with respect to the shutter 25. The objective lens 27 condenses the pulse laser beam and functions so that the pulse laser beam is focused on the recording layer 13. The position of the objective lens 27 is moved by a focus coil 41 (not shown) (see FIG. 4). Thereby, the focus of the pulse laser beam is controlled.

  The first light receiver 28 receives the pulse laser beam branched by the beam splitter 23 and receives this light. The received signal is input to the control device 100.

  The second light receiver 29 receives the light reflected from the optical recording disk 10 and further branched by the beam splitter 23 through the cylindrical lens 29a. The received signal is input to the control device 100.

  The optical pickup 20 as described above can be moved along the guide 33, that is, along the radial direction of the optical recording disk 10 by a known actuator 35 as an example of a scanning device.

  As shown in FIG. 4, the control device 100 receives data to be recorded and, based on the signals input from the first light receiver 28 and the second light receiver 29, the laser 22, the shutter 25, the actuator 35, and the motor. 32, a device for controlling the focus coil 41, the modulation circuit 110, the synchronization signal generation circuit 115, the light emission drive means 120, the shutter drive means 130, the optical pickup moving means 145, the rotation drive means 150, the focus calculation means 160, the focus drive. Means 161 and a storage unit 190 are provided. Each means is configured by a dedicated circuit or realized by causing a computer including a CPU, a ROM, a RAM, and the like to execute a program.

  The modulation circuit 110 is an example of a modulation unit, and is a circuit that modulates data to be recorded into digital data (hereinafter referred to as “pit arrangement data”) indicating the arrangement of pits. As the modulation circuit 110, for example, a known EFM modulation circuit or the like can be used.

  The synchronization signal generation circuit 115 is a circuit that receives a light intensity signal received by the first light receiver 28 and generates a synchronization signal at the same timing (frequency) as this signal. This signal is used to synchronize the operations of the shutter driving unit 130, the optical pickup moving unit 145, and the rotation driving unit 150. The synchronization signal generated by the synchronization signal generation circuit 115 is not necessarily based on the light reception signal from the first light receiver 28.

  The light emission drive means 120 is a known means for outputting a drive signal for causing the laser 22 to emit light to the laser 22.

  The shutter driving unit 130 is a unit that drives the shutter 25 in accordance with the pit arrangement data input from the modulation circuit 110. The shutter driving unit 130 converts the pulsed laser light emitted at a constant period into pulsed light that blinks in a pattern corresponding to the pit arrangement data by thinning out the pulsed light emitted by the laser 22 as appropriate. The pulsed light after the thinning may correspond to a plurality of pulsed lights in one pit. Thereby, a plurality of types of pit lengths can be formed. Note that the operation timing of the shutter driving unit 130 is determined according to the synchronization signal.

  The optical pickup moving means 145 drives the actuator 35 at a predetermined speed so as to form a recording track in a spiral shape on the optical recording disk 10 in the same manner as a known optical recording disk drive. As a result, the optical pickup 20 is sequentially moved from the inner diameter side to the outer diameter side of the optical recording disk 10 and from the outer diameter side to the inner diameter side. The optical pickup moving means 145 receives a synchronization signal from the synchronization signal generating circuit 115, and the moving speed of the optical pickup 20 is adjusted according to this synchronization signal.

The rotation driving means 150 is a known means for driving the motor 32 to drive the optical recording disk 10 to rotate. The rotation driving means 150 receives a synchronization signal from the synchronization signal generation circuit 115 and adjusts the rotation speed in accordance with the synchronization signal.
This rotational speed is preferably set to a speed at which pulsed light that is continuously emitted in a constant cycle of the pulsed laser light is irradiated in a circumferential direction of the optical recording disk 10. Thereby, as described above, the length of the pits can be adjusted by the number of pulsed lights that are continuously emitted. That is, pits having a plurality of types of lengths can be formed.

  The focus calculation unit 160 is a unit that receives a light reception signal from the second light receiver 29 and calculates the focus control amount of the objective lens 27. The focus calculating unit 160 calculates a focus control amount by, for example, a known astigmatism method. Further, the focus calculation means 160 determines and stores the position of the information recording layer currently recorded, and determines the focus control amount in accordance with the position of the information recording layer. The calculation result is output to the focus driving means 161.

  The focus driving unit 161 is a unit that outputs a signal to the focus coil 41 in accordance with the focus control amount calculated by the focus calculation unit 160.

  The focus calculation means 160 is a region where data is not recorded, such as the inner diameter side edge or the outer diameter side edge of the optical recording disk 10 when moving the focus position between the information recording layers 15 and 16. The focus control amount is calculated at a position moved to an area outside the data recording range preset in the unit. That is, the control device 100 moves the optical pickup 20 to an unrecorded area by the optical pickup moving unit 145, and focuses the laser beam on the interface between the recording layer 13 and the intermediate layer 12 by the focus calculating unit 160. . Thereafter, the optical pickup 20 is moved to a predetermined recording area, and information is recorded in a layer of the recording layer 13 adjacent to the interface with the intermediate layer 12.

  The storage unit 190 is a part that stores data as appropriate during the calculation performed by the control device 100. For example, calculation data at the time of modulation in the modulation circuit 110, the positions of the information recording layers 15 and 16 currently being recorded, the positions of the focused information recording layers 15 and 16 and the like are stored.

The operation of the optical recording disk drive 1 configured as described above will be described.
Data input to the control device 100 from a computer (PC) or the like is modulated into pit arrangement data by the modulation circuit 110.
Then, the rotation driving unit 150 rotates the optical recording disk 10 by rotating the motor 32 at a predetermined rotation speed.

  Before starting recording, the control device 100 moves the optical pickup 20 to a recording position, and focuses the information recording layer to be irradiated (focused) with the optical pickup 20. Therefore, for example, the actuator 35 is driven to move the optical pickup 20 to an unrecorded position on the inner diameter side, and focusing on the information recording layer to be recorded is performed. As an example method, the second light receiver 29 detects a change in brightness while focusing on the interface between the uppermost recording layer 13 and the intermediate layer 12 and then gradually increasing the focus position. Count the number of interfaces. If this count corresponds to the layer to be recorded, the current applied to the focus coil 41 is finely adjusted by the focus driving means 161 to adjust the focus to the position of the information recording layer to be recorded. Next, the actuator 35 is driven to move the optical pickup 20 in the radial direction of the optical recording disk 10 to move the optical pickup 20 to a position corresponding to the recording position in the information recording layer.

  When the optical pickup 20 is moved to a position corresponding to the recording position, the light emission drive unit 120 drives the laser 22, and intermittent pulsed laser light is emitted from the laser 22. The shutter driving unit 130 operates the shutter 25 according to the pit arrangement data generated by the modulation circuit 110. Thereby, in accordance with the pit arrangement data, the information recording layer of the recording layer 13 is irradiated with pulse laser light, and a two-photon absorption reaction occurs in the irradiated portion, and the refractive index changes.

  In this way, for example, a recording region in which the refractive index is changed is formed only in a region (information recording layer 16) adjacent to the interface with the lower intermediate layer 12 in the recording layer 13, such as the pit P1 in FIG. Is done.

  After the recording on the information recording layer 16 is completed on the entire surface of the optical recording disk 10, the focus calculating means 160 and the focus driving means 161 move the focus to the information recording layer 15 one above, and the above-described process Similarly to the above, information is recorded by driving the shutter 25 in accordance with the pit arrangement data. As a result, the refractive index changes only in the region (information recording layer 15) adjacent to the interface with the upper intermediate layer 12 in the recording layer 13, and pits P2 are formed.

Next, it will be described that information can be recorded and reproduced by such a recording method.
The reflectivity R when light is incident on the interface of the material perpendicularly is such that the refractive index of one material (for example, the recording layer 13) is n1, and the refractive index of the other material (for example, the intermediate layer 12) is n2. Then, R = (n1−n2) ² / (n1 + n2) ² is given.
Here, assuming that the recording layer 13 has an unrecorded refractive index of 1.7, a post-recording refractive index of 1.8, and the intermediate layer 12 has a refractive index of 1.47, the reflectance R before recording. Is 0.53%, and the reflectance R after recording is 1.1%. This value is the same for both information recording layers 15 and 16.
In other words, after recording, the reflectance R is approximately twice that before recording, so that information can be recorded even when the reflectance R changes at one interface as in this embodiment.

  As described above, according to the recording method by the optical recording disk drive 1 of the present embodiment, the information recording layer 15 adjacent to the interface with the upper intermediate layer 12 and the lower intermediate layer are formed in one recording layer 13. Information is recorded on the two information recording layers of the information recording layer 16 adjacent to the interface with the layer 12. That is, since two information recordings can be performed on one recording layer 13, the number of recording layers 13 can be reduced if the same number of information recording layers as in the prior art is provided. It becomes possible to simplify.

  Further, as in the present embodiment, when focusing is performed on another information recording layer, focusing is performed in a region where no information is recorded, thereby making it possible to more reliably focus on a predetermined information recording layer.

  Although the embodiment of the present invention has been described above, it goes without saying that the present invention can be appropriately modified and implemented without departing from the spirit of the present invention.

For example, in the above-described embodiment, an optical recording disk is illustrated as an example of an optical recording medium. However, the optical recording medium does not necessarily have a disk shape, and may be a square card type medium.
In addition, as an example of the scanning device, the actuator 35 that moves the optical pickup 20 in the radial direction of the optical recording disk 10 is illustrated. However, the laser light is emitted by relatively moving at least one of the laser light and the optical recording medium. Since it is only necessary to irradiate the entire recording range of the recording medium, for example, scanning may be performed by deflecting laser light.

  In the embodiment, the intermediate layer 12 made of the same material is assumed for the first adjacent layer and the second adjacent layer. However, the first adjacent layer and the second adjacent layer are not necessarily the same and are different. Also good. For example, the layer above the uppermost recording layer 13 may be directly used as the cover layer 14.

1 is a diagram showing a schematic configuration of an optical recording disk recording apparatus according to an embodiment. It is an expanded sectional view of an optical recording disk. It is an enlarged view of an optical pickup. It is a block diagram of a control apparatus. It is an expanded sectional view of the optical recording disk explaining the position of the pit recorded on the optical recording disk.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical recording disk drive 10 Optical recording disk 11 Board | substrate 12 Intermediate | middle layer 13 Recording layer 14 Cover layer 15 Information recording layer 16 Information recording layer 20 Optical pick-up 22 Laser 25 Shutter 32 Motor 35 Actuator 41 Focus coil 100 Control apparatus

Claims (5)

A recording layer having a two-photon absorption compound capable of changing a refractive index upon exposure, a first adjacent layer adjacent to one side of the recording layer, and a second adjacent layer adjacent to the other side of the recording layer; An optical recording medium recording method comprising:
Of the recording layer, a laser beam focused on a region adjacent to the first interface with the first adjacent layer is irradiated to change the refractive index of only the adjacent region, and the reflectance of the first interface is changed. Forming a pit using the change of the information and recording information in the first layer in the recording layer;
Of the recording layer, a laser beam focused on a region adjacent to the second interface with the second adjacent layer is irradiated to change the refractive index of only the adjacent region, and the reflectance of the second interface is changed. Forming a pit using the change of the information and recording information in the second layer in the recording layer;
A method for recording an optical recording medium, comprising:   The optical recording medium includes a plurality of recording layers and an intermediate layer sandwiching each recording layer, and the intermediate layer is the first adjacent layer or the second adjacent layer. Item 8. A recording method for an optical recording medium according to Item 1. A recording layer having a two-photon absorption compound capable of changing a refractive index upon exposure, a first adjacent layer adjacent to one side of the recording layer, and a second adjacent layer adjacent to the other side of the recording layer; A method of manufacturing an optical recording medium on which information is recorded,
Of the recording layer, a laser beam focused on a region adjacent to the first interface with the first adjacent layer is irradiated to change the refractive index of only the adjacent region, and the reflectance of the first interface is changed. Forming a pit using the change of the information and recording information in the first layer in the recording layer;
Of the recording layer, a laser beam focused on a region adjacent to the second interface with the second adjacent layer is irradiated to change the refractive index of only the adjacent region, and the reflectance of the second interface is changed. Forming a pit using the change of the information and recording information in the second layer in the recording layer;
The manufacturing method of the recording medium on which the information characterized by having was recorded. A recording layer having a two-photon absorption compound capable of changing a refractive index upon exposure, a first adjacent layer adjacent to one side of the recording layer, and a second adjacent layer adjacent to the other side of the recording layer; An optical recording medium recording apparatus comprising:
A laser light source that emits laser light, an optical system that condenses the laser light emitted from the laser light source, a focus actuator that moves the optical system to adjust a focus position of the laser light, the laser light, and the optical recording medium A scanning device that moves the irradiation position of the laser beam on the optical recording medium by relatively moving at least one of the optical recording medium, and a control device that controls the scanning device and the focus actuator.
The controller is
The scanning device and the focus actuator are controlled to irradiate a focused laser beam on a region adjacent to the first interface with the first adjacent layer in the recording layer to thereby change the refractive index of only the adjacent region. Pits are formed using the change in reflectance of the first interface, information is recorded in the first layer in the recording layer, and the second of the recording layers with the second adjacent layer is recorded. Irradiate the focused laser beam to the area adjacent to the interface of the recording medium to change the refractive index of only the adjacent area, and form pits using the change in the reflectance of the second interface to A recording apparatus for recording information on a second layer. The control device controls the scanning device and the focus actuator to focus laser light on the first interface or the second interface in a region where information is not recorded, and a layer in a region adjacent to the interface 5. The optical recording medium recording apparatus according to claim 4 , wherein information is recorded on the optical recording medium.

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