KR20070106251A - Data processing method and apparatus thereof and recording medium - Google Patents

Abstract

A data recording and playing method, a device thereof, and a recording medium are provided to improve data control speed when using the recording medium with multiple layers and to control the plural data simultaneously. In a data recording and playing method, a path of a beam irradiated to a recording medium is separated in plural paths. A focus adjustment unit(20,21) is positioned to at least one of the separated path. The beam irradiated through the different separated path is irradiated to a different layer of the recording medium. The focus adjustment unit changes an incident ray of the beam irradiated to an objective lens unit(100) collecting the beam at the recording medium. A data recording and playing device includes a beam source(10), a path separating unit(15) and the objective lens unit additionally. The path separating unit divides the path of the beam in the plural paths. The objective lens unit irradiates the incident ray entered through the separated path, to the recording medium. In the recording medium, one of the irradiated beams is irradiated at a layer with position information to provide the position information and the other irradiated beam controls the data of the different layer thereof.

Description

Data processing method and apparatus approximately and recording medium

1 shows a drive and a disc of a general recording and reproducing apparatus.

Fig. 2 is a diagram showing the configuration of the first preferred embodiment of the optical system in the data recording and reproducing apparatus of the present invention.

3 is a view showing a focus adjusting unit constituting a preferred embodiment of the present invention.

Fig. 4 is a diagram showing an objective lens unit together with a recording medium, which constitutes a preferred embodiment of the present invention.

5 is a block diagram showing the configuration of a data recording and reproducing apparatus which constitutes a preferred embodiment of the present invention.

Fig. 6 is a diagram showing the configuration of the second preferred embodiment of the optical system in the data recording and reproducing apparatus of the present invention.

Fig. 7 is a diagram showing the configuration of the third preferred embodiment of the optical system in the data recording and reproducing apparatus of the present invention.

8 is a partial sectional view showing the structure of a recording medium constituting a preferred embodiment of the present invention.

* Description of the symbols for the main parts of the drawings *

10: light source 15: path separation unit

16, 24, 26: reflector 17, 18: polarization conversion surface

20, 21: focusing unit 25: separation synthesis unit

30: condenser lens 31: near-field lens

40, 60, 80: optical separation unit 50, 70, 90: light receiving unit

100: objective lens unit 200: recording medium

300: signal generator 400: controller

500: optical system

The present invention relates to a data recording and reproducing method and apparatus and a recording medium, and more particularly, to a method and apparatus for processing data such as recording or reproducing efficiently by improving the processing speed of data and a recording medium used therefor. .

A data recording and reproducing apparatus using light records data on or reproduces recorded data using an optical disk such as a compact disc (CD) or a digital versatile disc (DVD) as a recording medium. The information recording medium used for this is actively researched for high density according to the demand for high quality video processing and the development of video extrusion technology. However, due to the optical and physical limitations caused by the conventional optical recording method or the magneto-optical recording method, the recording capacity has not reached a satisfactory level.

In the above recording medium, the recording density may depend on the diameter of light irradiated to the data recording layer of the recording medium. In other words, the smaller the diameter of the focused light irradiated onto the recording medium, the higher the recording density. At this time, the diameter of the focused light is largely determined by two factors. One is the number of effective apertures (Numeric Aperture, NA), which is the performance of a lens used for focusing light, and the other is the wavelength of light focused to the lens.

Since the focused light increases the recording density as the wavelength is shorter, light having a shorter wavelength is used as a method for increasing the recording density. In other words, when blue light is used as compared with red light, the recording density can be further increased, and a blue-ray disk is used. However, when a general lens is used, there is a limit to reducing the diameter of the light because there is a diffraction limit of the light. Accordingly, a near field recording (NFR) device using near field optics capable of storing or reading information in units smaller than the wavelength of light has been developed.

On the other hand, there is a need for a recording / reproducing apparatus having a high speed of recording or reproducing in terms of backing up or using information (Data) in addition to the above aspect of capacity. For example, a 25GB Blue-ray disk can record and play two hours of HD movies, and when used as an information storage device, it can record up to about 12 minutes when it is recorded at a maximum speed of 10 times. On the other hand, high-capacity storage devices larger than 200GB are greatly affected by the transmission speed in recording or playback time. For example, when recording or playing back information of 200GB, the time required to read at the speed of the blue-ray disk requires about 10 times, so the increase in capacity must be accompanied by an increase in recording and playback speed.

1 shows a drive and a disc of a general recording and reproducing apparatus. When the disk 1 is inserted into the disk seating portion 3 of the drive 2 as shown, the light 1 is irradiated and inserted through the pick-up P provided in the drive 2. Record or play back data.

The optical system (not shown) provided inside the pickup P includes an objective lens (not shown) for irradiating the recording medium 1 with light emitted from a light source. Then, the objective lens is moved to adjust the position of light irradiated onto the recording medium. In such a recording / reproducing apparatus, it is difficult to increase the rotational speed of the disk to 1000 rpm or more, which is the current maximum, as one of the methods for improving the data processing speed.

Another approach may be to consider a method of simultaneously processing a plurality of data on the recording medium in order to improve the data processing speed. However, the conventional recording and reproducing apparatus has a problem that it is difficult to process data in two recording layers at the same time since the objective lens is moved to change the position of light irradiated onto the recording medium.

Recently, a recording and reproducing apparatus using a near field that forms an objective lens together with a lens having a high refractive index to form an evanescent wave below the diffraction limit has been developed. Here, the near field recording / reproducing apparatus has a limitation on the movement of the object lens because the objective lens must maintain a very close distance of 100 nm or less to form the near field. Therefore, it is difficult to use a recording medium in multiple layers, and therefore, there is a problem that it is difficult to simultaneously process data in multiple recording layers.

Accordingly, the present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide a method and apparatus for improving the data processing speed when using a multi-layer recording medium.

It is another object of the present invention to provide a recording medium for use in a data recording and reproducing method and apparatus capable of simultaneously processing a plurality of data.

According to a feature of the present invention for achieving the above object, the data recording and reproducing method of the present invention separates a plurality of paths of light irradiated onto a recording medium, and the focus control unit in at least one of the separated paths; In addition, the light irradiated through the separated different paths can be irradiated to different layers of the recording medium.

The focus adjusting unit is a part for changing an incident angle of light incident on the objective lens unit focusing light on the recording medium. Specifically, at least one movable lens may be included, and the distance to the objective lens unit may be adjusted by moving the lens in the optical axis direction. Specifically, for example, it may be configured to include a fixed first lens and a movable second lens.

The objective lens unit includes a focusing lens for focusing light and a near field lens provided on an optical path passing through the focusing lens and irradiated onto the recording medium, wherein the near field lens is controlled to maintain a predetermined distance from the recording medium.

Here, the light irradiated through the separated different paths may be configured to have different polarized directions of the light, and the light sources from which the light is emitted may be configured differently.

Meanwhile, a track error signal or a gap error signal may be generated using any one of light reflected and reflected from different layers of the recording medium to control the apparatus for implementing the recording / reproducing method.

The data recording and reproducing apparatus of the present invention includes a focus adjusting unit which is provided in at least one of a light source for emitting light, a path separating unit for separating a plurality of light paths, and at least one of the separated optical paths, and changes the path of the light. And an objective lens unit for irradiating the recording medium with the light incident through the separated path. The display device may further include a polarization conversion surface provided in at least one path of the separated optical paths and converting the polarization direction of the light.

The focus adjuster may include at least one movable lens, and is a portion that changes an incident angle of light incident on the objective lens according to the movement of the lens. Specifically, the first lens may include a first lens having a fixed position and a second lens that may move the position.

And the objective lens unit includes a focusing lens for focusing the light and a near-field lens provided on an optical path passing through the focusing lens and irradiated onto the recording medium, wherein the near-field lens is controlled to maintain a predetermined distance from the recording medium. Can be configured.

On the other hand, the data recording and reproducing apparatus constituting another embodiment of the present invention is provided in at least one path of a plurality of light sources for emitting light and optical paths emitted from the different light sources and traveling through different paths. And a focus adjusting unit for changing the path of the light and an objective lens unit for irradiating the recording medium with light incident through the different paths. The display device may further include a polarization conversion surface provided in at least one path among the different paths and converting the polarization direction of the light.

Here, the focus adjusting unit includes at least one movable lens, and is a portion for changing the incident angle of light incident on the objective lens according to the movement of the lens, as described above.

In addition, the data recording and reproducing apparatus, the light emitted from any one of the light source is irradiated to the layer provided with the position information of the recording medium, the light emitted from the other light source is changed in the incident angle by the focus adjustment unit It can be configured to irradiate different layers of the recording medium.

On the other hand, the recording medium of the present invention includes a plurality of data recording layers, wherein position information is provided on any one of the recording layers, and any one of the plurality of lights irradiated to the recording medium is provided with the position information. Irradiated to provide positional information, and other light may be configured to process data in different recording layers of the recording medium.

In this case, the position information of the track may be provided in a wobbling manner, and the position information of the track may be provided in a data recording layer closest to the direction in which light is irradiated onto the recording medium.

Hereinafter, with reference to the accompanying drawings, a preferred embodiment of the data recording and reproducing method and apparatus and the recording medium according to the present invention as described above will be described in detail. In adding reference numerals to the components of the following drawings, for the sake of understanding, the same components are used as much as possible even if they are displayed on different drawings.

2 is a view showing the configuration of an optical system constituting an embodiment of a data recording and reproducing apparatus according to the present invention, FIG. 3 shows a focus control unit included in the optical system, and FIG. 4 is an object constituting the optical system. The lens portion is shown together with the recording medium. 5 is a block diagram showing the configuration of a data recording and reproducing apparatus including the optical system.

Hereinafter, a first preferred embodiment of the present invention will be described in detail with reference to the drawings. This embodiment includes one light source 10 as shown, and the light source preferably uses a laser light source with good straightness. To this end, the light source 10 may use a laser diode.

The light emitted from the light source 10 passes through the path separation unit 15 and is separated into light having a plurality of different paths. Here, the path splitter 15 may be separated into a plurality of parts using a diffraction grating or may be separated according to the polarization direction using an optical element such as a beam splitter. In the present embodiment, for example, a beam splitter is used to separate a path of light into two paths according to the polarization direction. For example, various changes are possible as long as light separates the path.

Specifically, the path separation unit 15 separates incident light according to the polarization direction. For example, x-axis polarization may be transmitted and y-axis polarization may be reflected according to the polarization direction. Here, the polarization direction is determined based on the vibration direction of the electric field, and the case where the electric field vibrates in the x-axis direction on a plane perpendicular to the traveling direction of the wavelength is called x-ray polarization, and the electric field vibrates in the y-axis direction. The case is called y-axis polarization

Focus adjustment units 20 and 21 are provided on a path toward the separated x-axis polarization and y-axis polarization to the separation synthesis unit 25 which will be described later. The focus adjusting units 20 and 21 are parts for converting incident angles of light incident to the objective lens unit 100 to be described later.

The focus adjusters 20 and 21 may be provided only for one of the x-axis polarization and the y-axis polarization (that is, when only one of 20 or 21 is provided), and both may be provided. Preferably, since the x-axis polarization and the y-axis polarization both include a focus adjusting unit on the optical axis, this case is illustrated in FIG. 2, and the focus adjusting unit will be described later in detail with reference to FIGS. 3 and 4.

The x-axis polarization and the y-axis polarization, whose paths are converted to have different angles of incidence by the focus adjusters 20 and 21, have the same path by the separation synthesizer 25, and the objective lens unit ( Incident to 100).

Here, the separation synthesis unit 25 is a part for transmitting or reflecting light according to the polarization direction to separate or synthesize two lights having different polarization directions. For example, the x-axis polarized light incident on the separation compound part 25 is transmitted and the y-axis polarized light incident with a difference of 90 ° is reflected to reflect the x-axis polarized light and the y-axis polarized light incident on the separation compound part 25. Can be synthesized to proceed in the same direction. On the contrary, the x-axis polarization component of the light incident on the separation synthesis unit 25 may be transmitted through the same path, and the y-axis polarization may be reflected to be separated by a 90 ° difference.

Each part can be provided with a plurality of optical elements as necessary. That is, a plurality of light separation parts 40, 60, and 80 are provided, wherein the light separation parts 40, 60, and 80 are parts for converting the path of incident light. For example, the x-axis polarization may be transmitted and the y-axis polarization may be reflected according to the polarization direction to change the traveling direction of the light according to the polarization direction. Specifically, the optical splitters 40, 60, and 80 may use a beam splitter or a polarized beam splitter (PBS).

In addition, polarization conversion surfaces 17 and 18 are further provided on a path of the light transmitted through the light separation parts 40, 41, and 60. The polarization converting surfaces 17 and 18 are portions for converting linearly polarized light into circularly polarized light or for converting circularly polarized light into linearly polarized light. For example, if the x-axis polarized light passes through each of the optical separation parts 40, 60, and 80 and passes through the polarization converting surfaces 17, 18, circular oscillation or circular oscillation is performed. Left circularly polarized light can be formed.

Specifically, the configuration of the light separation unit 40, 60, 80 divides the light incident by the birefringent crystal into normal light and abnormal light to proceed at different speeds. Preferably, a quarter-wave plate may be used in which two components formed when light having a wavelength of λ are transmitted have optical path differences of λ / 4 with each other. Here, the linearly polarized light oscillating with the optical path difference of λ / 4 is synthesized to form circularly polarized light with constant amplitude in a plane perpendicular to the traveling direction.

Here, it is also possible to reduce the number of optical elements provided separately by configuring one surface of the above-described optical separation unit 40, 60, 80 as the polarization conversion surface (17, 18).

In addition, a plurality of reflecting mirrors (16, 24, 26) is provided, the reflecting mirrors (16, 24, 26) is a portion for changing the direction of the light by total reflection of the incident light.

Hereinafter, the focus adjusting units 20 and 21 will be described in detail with reference to FIGS. 3 and 4. The focus adjusters 20 and 21 include at least one lens movable on an optical axis, and move the lens to convert an incident angle of light. To this end, the focus adjusters 20 and 21 may be configured as one movable lens to simplify the optical system, or may be configured by arranging a plurality of lenses including a convex lens or a concave lens to enable fine adjustment. .

The configuration of the optical system is as simple as possible, but in the case of only one lens, fine adjustment is difficult. Therefore, the optical system is preferably composed of two convex lenses (the first lens 20a and the second lens 20b). This case will be described as an example.

Here, the first lens 20a may be moved back and forth on the optical axis, and the movable range is preferably limited to the range of focal length at which the light passing through the objective lens unit 100 is irradiated onto the recording medium 200. . In addition, since the control is difficult when both lenses are movable, the position of the second lens 20b is preferably fixed.

3 illustrates a path of light incident on the first focusing unit 20 and the first focusing unit 20 including the movable first lens 20a and the fixed second lens 20b together. Illustrated. As shown, when the first lens 20a is positioned at A, light incident in parallel is focused on the focal point at the first lens 20a and is incident on the second lens 20b. When the first lens 20a moves to B, the light incident in parallel is incident to the B position in parallel and then refracted by the first lens 20a to enter the second lens 20b. Therefore, as shown in FIG. 1, the traveling directions of the light passing through the second lens 20b are different from each other as the position of the first lens 20a moves. That is, the incident angle of the light incident on the objective lens unit 100, which will be described later, changes.

4 illustrates the path of the light traveling together with the recording medium 200 when light having different incidence angles is incident on the objective lens unit 100 as described above. In order to clearly show the difference here, the first light (shown by the dotted line) and the second light (shown by the solid line) are shown as oblique light having an inclination with respect to the parallel light and the normal line, respectively.

As the first light is incident and refracted in parallel to the condenser lens 30, the first light is irradiated to the first data recording layer L ₀ . The second light incident at a relatively oblique angle is refracted by the condenser lens 30 and irradiated onto the second data recording layer L ₁ . In this way, the position of the light irradiated onto the recording medium 20 can be adjusted by changing the incident angle of the light incident on the objective lens unit 100 (specifically, the condenser lens 30).

The objective lens unit 100 may include only the condenser lens 30 that irradiates light onto the recording medium, and further includes a near field lens 31 on a path of light that is focused onto the recording medium through the condenser lens 30. It may include. Preferably, the present embodiment includes the focus adjusting units 20 and 21 separately from the objective lens unit 100. Since the objective lens unit 100 is more effective to be applied to the near field optical system where the movement of the objective lens unit 100 is not free, The optical system will be described as an example.

The near field optical system is configured such that the light focused by the condenser lens 30 passes through the near field lens 31 having a high refractive index. Here, the near field lens 31 is a lens having a high refractive index, and may use a solid immersion lens (SIL).

Here, the light incident on the near-field lens 31 at an angle greater than or equal to a critical angle passes through the inside of the lens having a high refractive index, and is totally reflected to form light having a small intensity on the surface of the near-field lens 31. That is, it forms an evanescent wave below the diffraction limit. The dissipation wave enables high resolution which was impossible due to the diffraction limit of the light wavelength when using one lens.

Here, when the near field lens 31 approaches the recording medium 200 at a very close distance within 100 nm, it forms an area in which the dissipation wave can be used, which is called a near-field. Preferably, the separation distance between the near field lens 31 and the recording medium 200 is 1/4 or less of the wavelength used. For convenience, a region using the original wavelength outside the region of the near field is called a far-field corresponding to the near field.

Therefore, when controlling the separation distance between the near-field lens 31 and the recording medium 200 and considering the aberration of the lens, the near-field optical system has a difficulty in freely moving the objective lens unit 100 up and down.

Hereinafter, the operation of the optical system of the data recording and reproducing apparatus according to the present invention will be described in detail with reference to the light path.

Light emitted from the light source 10 shown in FIG. 2 is incident on the path separator 15. The path separating unit 15 separates the light according to the polarization component. For example, the x-axis polarization component passes straight through the path separation unit 15 and the y-axis polarization component is reflected on the path separation unit 15.

The separated x-axis polarization and the y-axis polarization travel in different paths until they reach the separation compound 25. At this time, look at each progress path.

The x-axis polarization passes through the second optical separation unit 60 and the first optical separation unit 40 and passes through the first polarization conversion surface 17. At this time, the light transmitted through the first polarization converting surface 17 forms a left circular polarized light which oscillates in a counterclockwise direction.

The left circularly polarized light is incident on the first focus controller 20. In this case, the path is converted by the refraction corresponding to the position of the movable first lens 20a of the first focus adjusting unit and is incident to the separation compound part 25.

The y-axis polarized light passes through the third optical separation unit 80 and passes through the second polarization converting surface 18. At this time, the light transmitted through the second polarization converting surface 18 forms right circularly polarized light oscillating in a clockwise direction.

The right polarized light is incident on the second focus adjusting unit 21. Here, the path is converted by refraction in correspondence to the position of the movable third lens 21a of the second focus adjusting unit, and also enters into the separation synthesis unit 25.

In this case, the distance to the second lens 20b of the first lens 20a is adjusted differently from the distance to the fourth lens 21b of the third lens 21b. Then, the left circle polarization and the right circle polarization have a difference in the degree of refraction as shown in FIG. 3, and may be adjusted to be incident on the objective lens unit 100 with different incidence angles.

Since the light incident on the objective lens unit 100 has different incidence angles, different layers of the recording medium 200 are irradiated on the same principle as shown in FIG. 4. For example, the left circularly polarized light may be incident to the first data recording layer L ₀ and the right circularly polarized light may be adjusted to be incident to the second data recording layer L ₁ .

That is, by using one objective lens unit 100, two different data recording layers L ₀ and L ₁ may be irradiated with light to simultaneously perform data processing such as recording or reproduction.

Meanwhile, the left circle polarization and the right circle polarization irradiated to the different data recording layers L ₀ and L ₁ of the recording medium 200 are reflected by the respective data recording layers L ₀ and L ₁ , and then separated and separated 25. Since the incident light is different from each other and has different polarization characteristics, the separation and progression are separated from the separation synthesis part 25. That is, the left circularly polarized light passes through the separation synthesis unit 25, and the right circularly polarized light is reflected by the separation synthesis unit 25, and the light reflected by the recording medium 200 travels in different paths.

The left circularly polarized light again passes through the first polarization converting surface 17. At this time, the reflected light transmitted through the first polarization converting surface is converted into linearly polarized light of x-axis polarization, which is the first incident light, and y-axis polarization, having a phase difference of 90 ° in the vibration direction of the electric field. In addition, the y-axis polarized light does not penetrate the first optical splitter 40, which is initially transmitted, is reflected, and then enters the first light receiver 50.

On the other hand, since the objective lens unit constituting the present invention has an effective numerical aperture, which is a numerical aperture representing the performance of the lens by the entire focusing lens 30 and the near-field lens 31, the numerical aperture is larger than one. A phenomenon in which polarization is distorted occurs in a part of the light totally reflected on the near field lens 31. The distorted polarized light is transmitted through the first optical splitter 40 without being reflected by the first optical splitter 40 and is incident on the second optical splitter 60. The light is reflected by the second light splitter 60 and enters the second light receiver 71. As a result, the reflected light irradiated onto the first data recording layer L ₀ may be detected.

Meanwhile, the right circularly polarized light passes through the second polarization converting surface 18 and is converted into linearly polarized light of x-axis polarized light having a phase difference of 90 ° in the vibration direction of the electric field and y-axis polarized light, which is the first incident light. Therefore, the x-axis polarized light does not penetrate the third optical separation unit 80 that has been initially transmitted, and reflects the incident light to the third light receiving unit 90. Through this, the reflected light irradiated to the second data recording layer L ₁ may be detected separately from the reflected light irradiated to the first data recording layer L ₀ .

As described above, the data recording and reproducing apparatus according to the present invention can perform data processing such as recording or reproducing data by irradiating light to two data recording layers simultaneously using the optical system. In addition, the control signal may be generated and controlled by using the light reflected from the respective data recording layers L ₀ and L ₁ so that the data can be processed correctly.

Fig. 5 is a block diagram briefly showing the configuration of a data recording and reproducing apparatus that constitutes a preferred embodiment of the present invention. Although it can be used for data processing at a far field, it is preferable to use it for data processing at near field where the movement of the objective lens unit 100 is unnatural.

As shown in the drawing, the data recording and reproducing apparatus generates a signal using the above-described optical system 500 and the reflected light formed by the optical system 500 while maintaining a constant distance from the recording medium 200 to form a near field. And a control unit 400 for controlling the data recording and reproducing apparatus (specifically, the objective lens unit 100) by using the generated signal. The signal generator 300 includes an A / D converter that converts the received reflected light into a digital signal.

The reflected light detected by each of the light receiving units 50, 70, and 90 in the optical system 500 includes a recording frequency signal, a focus error signal (Focus Error Signa, FES), and a track error signal (Track Error Signal) for control. , TES), a gap error signal (GES), and the like.

The focus error signal FES is used to control the position at which light is irradiated when the distance between the objective lens unit 100 and the recording medium 200 changes due to surface vibration of the recording medium 200. The track error signal TES is used to control the objective lens unit 100 to follow a target track to be subjected to data processing. The gap error signal GES is used to maintain the distance between the objective lens unit 100 and the recording medium 200 in the above-mentioned near field data recording and reproducing apparatus.

Although the above-mentioned error signals can be generated using the signals reflected from the respective data recording layers, there is a fear that the configuration becomes complicated and unnecessary. The focus error signal FES and the recording / playback signal RF for adjusting the depth of focus are preferably generated separately and individually controlled using the light reflected on each data recording layer.

On the other hand, the track error signal TES and the gap error signal GES are more preferably generated using only one reflected light. The light irradiated at the same time by changing the incident angle of the light incident on the recording medium 200 by dividing the position of the focal point to which the light is irradiated up and down is irradiated to the same track position to be irradiated as shown in FIG. Therefore, it is sufficient to control whether or not the track follows using one reflected light.

As a specific example, the light reflected by the first data recording layer L ₀ is detected by the first light receiving unit 50 and the second light receiving unit 70. Here, the recording / reproducing signal RF and the track error signal TES are generated using the signal detected by the first light receiver 50, and the gap error signal GES is generated by using the signal detected by the second light receiver 70. Can be generated. The controller 400 may receive the generated error signal and control the data to be processed smoothly.

On the other hand, the light reflected by the second data recording layer L ₁ is detected by the third light receiving unit 90. The track error signal TES and the gap error signal GES are generated by using the signals detected by the first light receiver 50 and the second light receiver 70, and thus the reflected light detected by the third light receiver 90. It is sufficient to generate only the signal RF for recording and reproduction.

In addition, the optical system 500 constituting the present invention can be variously modified as long as it can irradiate a plurality of lights having different polarization directions at the same time as described above. Other preferred embodiments will be described with reference to FIGS. 6 and 7, where the same configuration and operation are the same as described above, and will be omitted and described based on differences.

In order to irradiate a plurality of lights, as in the first embodiment described above, the light emitted from one light source may be separated and used, and a plurality of light sources may be used. Hereinafter, a case in which two light sources are used will be described with reference to FIG. 6.

As shown, the light emitted from the first light source 10 and the light emitted from the second light source 11 are irradiated to the objective lens unit 100 through different paths. The path of each light is the same as the path in FIG. 2 separated from the one light source, and thus description thereof is omitted.

The first light source 10 and the second light source 11 may use a light source having a different wavelength or configure the output differently, and do not require an optical element such as a separate path separation unit. to provide.

In addition, in the case of using a plurality of lights or a plurality of light sources separated from one light source, the number of focus adjusting units may be one less than the number of light paths. For example, as shown in FIG. 7, since a separate focus control unit is not provided in the path of the light emitted from the first light source 10, it is irradiated to a predetermined data recording layer as in the case of using a conventional single layer recording medium. In addition, a focus adjusting unit 21 may be provided in the path of the light emitted from the second light source 10 to adjust the light to the second data recording layer L ₁ .

Further, as described above, a data recording / reproducing method capable of simultaneously processing a plurality of data and a recording medium used in the apparatus include a plurality of data recording layers. Each data recording layer provides information regarding the position of the current track or sector upon recording or playback. This may be expressed by wobbling and may be expressed in various ways.

The position information may be provided in all of the recording layers, and may be provided only in any one of the data recording layers provided in the recording medium. This will be described with reference to FIG. 8.

As shown, the recording medium may comprise a first data recording layer L ₀ provided with the position information 211 and a second data recording layer L ₁ provided without the position information. That is, preferably, the positional information may be provided only on the uppermost layer to which light is irradiated, that is, the illustrated first data recording layer L ₀ .

In the recording and reproducing method according to the present invention, one objective lens unit 100 is used, and the position of light irradiated to the recording medium 200-1 is changed by using a focus control unit separated from the objective lens unit 100. will be. Therefore, the track position information is the same even when the positions of the data recording layers irradiated on the recording medium are different. Accordingly, the positional information of the recording medium can be provided in only one data recording layer and can be shared by all data recording layers.

The operation of the recording / reproducing method using the recording medium 200-1 will now be described in detail. In this case, the recording and reproducing apparatus preferably does not include a focus adjusting portion in the path of the light emitted from the first light source 10 as shown in FIG. Therefore, in the present specification, an example will be described as a case of using a recording / reproducing apparatus composed of the optical system of FIG.

A first light emitted from the light source 10 is irradiated to the first data storage layer (L ₀₎ of the recording medium 200-1 reads the location information included in the first data storage layer (L _0). On the other hand, the light emitted from the second light source 11 is irradiated to the first data recording layer L ₀ or the second data recording layer L ₁ by the focus adjusting unit 21 provided on the optical path. You can record or play back. That is, the light irradiated from one light source provides position information provided in the first data recording layer L ₀ , and the light irradiated from another light source may receive the position information and perform data processing. In this case, when a plurality of lights are irradiated, data processing can be simultaneously performed on the plurality of data recording layers by using the positional information of the first data recording layer L ₀ . In this case, the first light source 10 may use a lower output than the second light source 11, and light having different wavelengths may be used.

In addition, since the recording medium 200-1 includes a plurality of data recording layers, it is preferable to include a spacer between each data recording layer to prevent interference between the data recording layers. The recording medium may further include a protective layer protecting a data recording layer on its surface.

The rights of the present invention are not limited to the embodiments described above, but are defined by the claims, and those skilled in the art can make various modifications and adaptations within the scope of the claims. It is self-evident.

The following effects can be expected in the data recording and reproducing method and apparatus and the recording medium according to the present invention as described in detail above.

That is, there is an advantage of improving the data processing speed by processing a plurality of data at the same time.

In addition, there is an advantage that data is efficiently processed by irradiating light to different data recording layers of the recording medium through one objective lens unit.

Claims (20)

Separating a plurality of paths of light irradiated onto the recording medium, and having a focus adjusting unit in at least one of the separated paths, And the light irradiated through the separated different paths is irradiated to different layers of the recording medium. The method of claim 1, wherein the focus adjusting unit, And an angle of incidence of light incident on the objective lens portion focusing light on the recording medium. The method of claim 2, wherein the focus adjustment unit, And at least one movable lens, wherein the lens is moved in an optical axis direction to adjust a distance to the objective lens unit. The method of claim 2, wherein the focus adjustment unit, And a second lens movable in position and a second lens movable in position. The method of claim 2, wherein the objective lens unit, A focusing lens for focusing light and a near-field lens provided on an optical path passing through the focusing lens and irradiated onto a recording medium, And the near field lens is controlled to maintain a predetermined distance from the recording medium. The method of claim 1, wherein the light irradiated through the separated different paths, And the polarized direction of the light is different from each other. The method of claim 1, wherein the light irradiated through the separated different paths, And a light source from which the light is emitted is different from each other. The recording and reproducing method according to claim 1, wherein And a track error signal or a gap error signal is generated using any one of the light reflected and reflected from different layers of the recording medium. A light source for emitting light; A path separator for separating the path of the light into a plurality; A focus adjusting unit provided in at least one path of the separated light paths to change a path of the light; And an objective lens unit for irradiating the recording medium with the light incident through the separated path. The data recording and reproducing apparatus according to claim 9, And a polarization converting surface provided in at least one of the separated optical paths and converting a polarization direction of the light. The method of claim 9, wherein the focus adjustment unit, And at least one movable lens, the angle of incidence of light incident on the objective lens according to the movement of the lens. The method of claim 9, wherein the focus adjustment unit, And a second lens having a fixed position and a second lens capable of moving the position. The method of claim 9, wherein the objective lens unit, A focusing lens for focusing the light and a near-field lens provided on an optical path passing through the focusing lens and irradiated on a recording medium, And the near field lens is controlled to maintain a predetermined distance from the recording medium. A plurality of light sources for emitting light; A focus adjusting unit provided in at least one path of the light paths emitted from the different light sources and traveling through the different paths to change the path of the light; And an objective lens unit for irradiating the recording medium with light incident through the different paths. The data recording and reproducing apparatus according to claim 14, And a polarization converting surface provided in at least one of the different paths and converting the polarization direction of the light. The method of claim 14, wherein the focus adjustment unit, And at least one movable lens, the angle of incidence of light incident on the objective lens according to the movement of the lens. The method of claim 14, The light emitted from one of the light sources is irradiated onto the layer provided with the positional information of the recording medium, And the light emitted from another light source is irradiated onto different layers of the recording medium by changing the incident angle by the focus adjusting unit. A recording medium comprising a plurality of data recording layers, Location information is provided on any one of the recording layers, Any one of a plurality of lights irradiated to the recording medium is irradiated to a layer provided with the position information to provide position information, and the other light processes data to different recording layers of the recording medium. media. The method of claim 17, And the position information is wobbling. The method of claim 17, wherein the position information of the track, And a data recording layer closest to the direction in which light is irradiated onto the recording medium.

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