KR20080006704A - Recording and/or reproducing apparatus, method thereof and discriminating method of medium - Google Patents

Abstract

A recording/reproducing device and a method thereof, and a recording medium discriminating method are provided to change a focusing position where a beam is irradiated to a recording medium and to distinguish the structure of the recording medium effectively. A recording/reproducing device comprises a lens unit, a focus control unit, a driving unit, a beam receiving unit, and a control unit. The lens unit collects and irradiates a beam which is emitted from a beam source. The focus control unit changes a focusing position where the beam is irradiated to the recording medium. The driving unit adjusts the focus control unit and scans the recording medium. The beam receiving unit receives the beam reflected to the recording medium and generates a signal. The control unit discriminates the recording medium by using the signal generated in the scanning process. A recording/reproducing method includes a step of scanning the focus of the recording medium by adjusting the focus control unit(S12); a step of detecting the structure of the recording medium by using change of the signal generated in the scanning process(S13); and a step of requesting insert of a new recording medium when the recording medium is not a target recording medium(S14).

Description

Recording and reproducing apparatus and method and discrimining method of recording medium {Recording and / or reproducing apparatus, method approximately and discriminating method of medium}

Fig. 1 is a block diagram showing an embodiment of the preferred recording and reproducing apparatus of the present invention.

2 is a block diagram showing an optical system of an optical pickup constituting a preferred embodiment of the present invention together with a recording medium.

Fig. 3 is a side sectional view showing a lens section together with a recording medium constituting a preferred embodiment of the present invention.

 4 is a side cross-sectional view showing an embodiment of a focus adjusting unit together with a lens unit constituting a preferred embodiment of the present invention.

5 is a side cross-sectional view schematically showing a focus control unit constituting a preferred embodiment of the present invention.

Fig. 6 is a side sectional view showing the relationship between the focus adjusting unit and the light irradiated to the recording medium, which constitute a preferred embodiment of the present invention.

FIG. 7 is a diagram showing a light receiving unit composed of a four-segment photodetector. FIG.

8 shows characteristics of an optical signal by the astigmatism method.

9 shows the form of the reflected light detected in the light receiving portion.

FIG. 10 is a correlation diagram showing a relationship between a change in focusing position and FE. FIG.

11 is a flowchart showing the procedure of the method of discriminating the recording medium constituting the preferred embodiment of the present invention.

12 is a schematic diagram illustrating a TE according to a change in a focused position.

Fig. 13 is a flowchart showing the procedure of the method for discriminating the recording medium constituting another preferred embodiment of the present invention.

14 is a flowchart showing a recording / reproducing method of the preferred embodiment of the present invention.

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

1: optical pickup (P / U) 2: RF and servo error generator

3: control unit 4: focus servo drive unit

5: Tracking Servo Drive 6: Decoder

7: Encoder 8: ATAPI I / F

9: micom 10: light source

20: lens unit 21: objective lens

22: near-field shaping lens 30,30a: focus adjustment unit

31: first lens 32: second lens

40: separation synthesizer 45: cylindrical lens

50: light receiver 80: recording medium

92: envelope

The present invention relates to a recording and reproducing apparatus and a method for discriminating a recording medium, and more particularly, to a method for efficiently determining a recording medium and a recording and reproducing method and method using the same.

In general, an optical recording / reproducing apparatus is an apparatus for reproducing data recorded on the recording medium or recording data on the recording medium using a recording medium such as a compact disc (CD) or a digital versatile disc (DVD) as a recording medium. As consumer preferences require high quality video processing and video compression technology develops, high density recording media are required. One of the key technologies necessary for developing a high density recording medium is an optical head, that is, a technology related to an optical pickup.

In the above recording medium, the recording density may depend on the diameter of light irradiated onto the 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 the lens used for focusing, 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.

However, in the case of a Far Field recorder head using a general lens, there is a limit in reducing the diameter of the light because of the 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.

The near field optical recording device using the near field forming lens obtains light below the diffraction limit by using the near field forming lens having a higher refractive index than the objective lens, and the light is propagated to the recording medium near the interface in the form of an evanescent wave. Stores high density bit information.

However, the prior art as described above has the following problems.

That is, in order to maintain the dissipation wave, it is difficult to change the focusing position by moving the objective lens itself because the lens must maintain a close distance to the recording medium.

In addition, since the structure information of the recording medium is grasped through the management information recorded on the recording medium, there is a problem that it takes a long time to determine whether it corresponds to the desired recording medium.

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 recording and reproducing apparatus and a method of varying the focus position irradiated to a recording medium.

Another object of the present invention is to provide a method for efficiently determining the structure of a recording medium.

According to a feature of the present invention for achieving the above object, the recording and reproducing apparatus of the present invention is provided on a lens unit for condensing or irradiating light emitted from a light source and a path of the light so that light is irradiated to the recording medium. A focus adjusting unit for varying a focus position, a driver adjusting the focus adjusting unit to scan a recording medium, a light receiving unit receiving light reflected from the recording medium and generating a signal, and a signal generated in the scanning process And a control unit for discriminating the recording medium.

The focus adjuster may include at least one adjustable lens to change the path of the light. For example, it may include a first lens having a fixed position and a second lens movable in the optical axis direction.

The controller generates information on the number, thickness, or position of the recording layer of the recording medium, in correspondence with the periodicity of the changing signal. For example, when the value of the focus error signal FE becomes 0, the focused position is determined as the position of the recording layer, or when the value of RF or TE becomes maximum, the focused position is determined as the position of the recording layer. Can be. Alternatively, when the value of the focus error signal FE becomes 0 and the value of RF or TE becomes maximum, the focused position may be determined as the position of the recording layer.

In addition, the recording and reproducing apparatus of the present invention is provided with an objective lens in order to use a near field, and is provided on a near field forming lens which forms a near field at intervals close to the recording medium, and is provided on a path of light emitted from a light source, A focus adjuster for varying the position of the focus irradiated to the recording medium, a driver for adjusting the focus adjuster to scan the recording medium, a light receiving unit for receiving the light reflected from the recording medium and generating a signal, and the scanning process And a controller for determining the recording medium by using the received signal.

The controller may generate information on the number, thickness, or position of the recording layer of the recording medium, corresponding to the periodicity of the signal generated during the scanning process, as described above.

On the other hand, the method of discriminating the recording medium of the present invention includes a lens for forming a near field and maintaining a distance between the recording medium and a focus adjusting unit provided on the optical path to change the position of the focus, wherein the focus adjusting unit is provided. By adjusting the scan of the focus of the recording medium, the structure of the recording medium can be determined by the change of the signal generated in the scanning process. For example, the number, thickness or position of the recording layer of the recording medium can be determined according to the periodicity of the signal change. That is, the recording medium can be determined by counting the number of times the value of the focus error signal becomes '0' or counting the number of times the value of the RF (RF) signal or the track error signal becomes the maximum.

In the recording and reproducing method of the present invention, in the recording and reproducing of a recording medium in the near field recording and reproducing apparatus, (a) adjusting the focus adjusting unit to scan the focus and (b) using the change of the signal generated in the scanning process. Determining the structure of the recording medium and (c) requesting the insertion of a new recording medium if the recording medium does not correspond to the target recording medium.

Hereinafter, the recording and reproducing apparatus and method according to the present invention as described above, and the method for discriminating the recording medium will be described in detail with reference to the drawings. As used herein, the term " recording medium " means any medium in which data is recorded or can be recorded, and specifically, an optical disk can be given. In addition, the term " recording / reproducing device " in the present specification means any device capable of recording data or reproducing the recorded data using the recording medium. However, in the present specification, for convenience of description, the movement of the objective lens is limited and the effective near field recording and reproducing apparatus of the present invention is described as an example, but the present invention is not limited to this embodiment.

In addition, the term used in the present invention was selected as a general term that is widely used as possible at present, but in certain cases there is a term arbitrarily selected by the applicant, in which case the meaning is described in detail in the description of the invention, It is to be understood that the present invention should be understood as the meaning of terms rather than names.

Fig. 1 schematically shows the configuration of a recording / reproducing apparatus constituting a preferred embodiment of the present invention. The configuration of the recording and reproducing apparatus will be described in detail with reference to Figs.

The optical pickup (P / U) 1 is a portion for irradiating light to a recording medium and condensing the light reflected on the recording medium to generate a signal. An optical system (not shown) constituting the optical pickup 1 may be configured as shown in FIG. 2. That is, the optical system provided in the optical pickup 1 includes a light source 10, a lens unit 20, a focus adjusting unit 30, a separation synthesis unit 40, and a light receiving unit 50.

As the light source 10, a laser or the like having good directivity may be used. Therefore, the light source 10 is specifically a laser diode. The light emitted from the light source 10 and to be irradiated onto the recording medium may be composed of parallel light. Therefore, it can be configured to include a lens, such as a collimate, to parallel the path of light on the path of light emitted from the light source.

The lens unit 20 is a portion that irradiates the recording medium 80 with the light emitted from the light source 10 and condenses the light reflected by the recording medium 80. Specifically, as shown in FIG. 3, the lens unit 20 constituting the preferred embodiment of the present invention has a path on the path through which the light passing through the objective lens 21 and the objective lens 21 enters the recording medium. It includes a near field forming lens 22 provided in. That is, by providing the near field forming lens 22 having a high refractive index in addition to the objective lens 21, the numerical aperture of the lens unit 20 is increased to thereby form an evanescent wave. Here, the near field forming lens 22 may specifically use a solid immersion lens (SIL), for example, a hemispherical or ultra hemispherical shape formed by cutting a spherical lens (a sphere having a middle height between a sphere and a hemisphere). A part of is called the early hemisphere).

In addition, the optical system 100 of the optical pickup including the lens unit 20 is located very close to the recording medium 80. The concrete example will be described as follows. When the lens portion 40 (specifically referred to as a near field forming lens) and the recording medium 80 are brought close to about 1/4 or less of the optical wavelength (that is, λ / 4) or less, the inside of the lens portion 20 The generated dissipation wave maintains its properties and can be used for recording and reproducing. However, when the distance between the lens unit 20 and the recording medium 80 is greater than λ / 4 or more, the wavelength of the light loses the property of the dissipated wave and returns to the original wavelength. Therefore, in the recording and reproducing apparatus using the near field, the lens unit 20 is maintained so that the distance from the recording medium 50 does not exceed approximately [lambda] / 4. Is the limit of the near field.

The focus adjusting unit 30 is a portion for changing the focus position of light irradiated onto the recording medium 80. For example, as shown in FIG. 4, the focus adjusting unit 30 may change the position of the focus by changing a traveling path of the light incident on the lens unit 20. Therefore, the focus adjusting unit 30 may include at least one movable lens 30a provided on the optical axis separately from the lens unit 20. Therefore, as shown, only one movable lens 30a can be configured. According to the present exemplary embodiment, the light traveling along the dotted line is changed by the focus adjusting unit 30a to travel along the solid line. By moving the focus adjuster 30a in the optical axis direction, the position at which light is irradiated onto the recording medium 80 can be varied.

According to another preferred embodiment of the present invention, the focus adjuster 30 includes two lenses as shown in FIG. 5, wherein the first lens 31 is fixed and the second lens 32 is movable. Can be configured to That is, the second lens 32 is configured to be positioned at the focus f where the light passing through the first lens 31 is focused or to move along the optical axis to the inside or the outside of the focus f.

Here, the light passing through the first lens 31 forms divergent light, convergent light, or parallel light according to the position of the second lens 32. That is, the light passing through the first lens 31 diverges or further focuses the path of light focused toward the focus f according to the position of the second lens 32 so that the path of the light is changed. For example, as illustrated in FIG. 6, the light irradiated onto the recording medium 80 by the lens unit 20 is generated when the second lens 32 is at the first position 32a (in a solid line). Display) is focused on the surface of the recording medium 80. On the other hand, the light irradiated onto the recording medium 80 is focused inside the recording medium 80 when the second lens 32 is at the second position 32b (indicated by the dotted lines). As a result, the focus adjusting unit 30 may be adjusted without moving the lens unit 20 to change the position of the light focused on the recording medium 80.

Here, the movable second lens 32 may be configured to have a thickness thinner than that of the first lens 31 to enable fine adjustment of the optical path. In addition, the lens constituting the focus adjusting unit 30 may be composed of a combination of a convex lens and a concave lens, to change the focus position of the light irradiated through the lens unit 20 as an embodiment of the present invention. Note that it is not limited to.

The separation and synthesis unit 40 of FIG. 2 is a part that separates paths of light incident in the same direction or synthesizes paths of light incident in different directions. In the present embodiment, the separation synthesis unit 40 may be configured to pass only polarization in a specific direction according to the polarization direction. For example, the separation composition part 40 may be configured to pass only the polarization component in the vertical direction and reflect the polarization component in the horizontal direction. Alternatively, it may be configured to pass only the polarization component in the horizontal direction and reflect the polarization component in the vertical direction. As a result, the separation synthesis unit 40 changes the path of the reflected light to be incident to the light receiving unit to be described later.

The light receiving unit 50 is a portion that receives and photoelectrically converts the reflected light to generate an electrical signal corresponding to the amount of the reflected light. In the present embodiment, as shown in FIG. 7, the light receiving unit 50 includes four photodetecting elements (PDA, PDB, etc.), each of which is specifically divided into a signal track direction and a radial direction of the recording medium 80. PDC, PDD). Each of the photodetecting elements PDA, PDB, PDC, and PDD generates electrical signals a, b, c, and d proportional to the amount of light received. Here, the configuration of the photodetecting device constituting the light receiving unit 50 is not limited to the present embodiment, and may be divided into two or other configurations as necessary.

The RF and servo error generation unit 2 of FIG. 1 uses the signal generated by the optical pickup 1 to produce an RF signal RF for data reproduction, a tracking error signal TE for servo control, and a focus error. To generate a signal FE and the like. For example, the RF may be obtained by (a + b + c + d) the electrical signal generated by the light receiving unit, and the (a + d) − (b + c) electrical signal generated by the light receiving unit may be used to obtain the RF. Can be obtained.

The control unit 3 receives a signal generated by the light receiving unit or the RF and servo error generating unit 2 and generates a control signal or a driving signal. For example, the FE is signal-processed to output a drive signal for focusing control to the focus servo driver 4, and the TE signal is processed to output a drive signal for tracking control to the tracking servo driver 5.

The focus servo driver 4 moves the optical pickup 1 or the lens 20 of the optical pickup up and down by driving a focus actuator (not shown) in the optical pickup 1. As a result, the optical pickup 1 or the lens unit 20 of the optical pickup can track the vertical movement with the rotation of the recording medium 80. In addition, the focus servo driver 4 may adjust the focus adjuster 30 of the optical pickup to change the focus of the light irradiated onto the recording medium 80. Here, the driving unit for driving the focus adjusting unit 30 may be provided separately.

The tracking servo driver 9 drives a tracking actuator (not shown) in the optical pickup 1 to move the optical pickup 1 or the lens portion 20 of the optical pickup in the radial direction to adjust the position of the light. Correct it. As a result, the optical pickup 1 or the lens unit 20 of the optical pickup can follow a predetermined track provided on the recording medium 80.

A host such as a PC may be connected to the recording and reproducing apparatus as described above. The host transmits a recording / reproducing command to the microcomputer 9 through the interface, receives the reproduced data from the decoder 6, and transmits data to be recorded to the encoder 7. The microcomputer 9 controls the decoder 6, the encoder 7, and the controller 3 according to the recording / reproducing command of the host. In this case, the interface may use an ATAPI (Advanced Technology Attached Packet Interface) 8. Here, ATAPI (8) is an interface standard between an optical recording / playback device such as a CD or DVD drive and a host, and it is a standard proposed to transmit data decoded by an optical recording / playback device to a host, and the decoded data is processed by the host. It converts and transmits the packet data which is possible data.

Hereinafter, in the pickup constituting the embodiment of the recording and reproducing apparatus, the operation sequence will be described in detail based on the traveling direction of the light emitted from the light source 10 within the optical system 100 and on the basis of the flow of signals other than the above. do.

The light emitted from the light source 10 inside the optical pickup 1 passes through the separation and synthesis unit 40 and enters the focus adjusting unit 30. As described above with reference to FIGS. 4 to 6, the light is incident on the lens unit 20 in different paths according to the position of the focus adjusting unit 30. Therefore, the focus position of the light irradiated onto the recording medium 80 moves constantly when the focus adjusting unit 30 constantly moves in the optical axis direction.

Light incident on the objective lens 21 of the lens unit 20 passes through the near field forming lens 42 to form a dissipation wave. Specifically, light incident on the near field forming lens 22 at an angle equal to or greater than the critical angle is totally reflected on the surface of the lens and the surface of the recording medium 80. Light incident on the near field forming lens 22 at an angle not exceeding the critical angle is reflected on the recording layer of the recording medium 80. Dissipation is generated in this process.

The light reflected by the recording medium 80 again enters the separation and synthesis unit 40 through the lens unit 20. In this case, a polarization converting surface (not shown) may be provided on a path incident to the separation and synthesis unit 30. The polarization converting surface converts the polarization directions of the light incident on the recording medium 80 and the reflected light. For example, when a quarter wave plate (QWP) is used as the polarization converting surface, the quarter wave plate polarizes the light incident on the recording medium 80 in a left circle, and the reflected light proceeds in the reverse direction. Polarize. As a result, the reflected light passing through the quarter wave plate is converted in the polarization direction in a direction different from the incident light, and has a difference of 90 degrees from each other. Therefore, the light incident only by the horizontally polarized component passed by the separating composition part 40 is reflected by the recording medium 80 to have a vertically polarizing component when it is incident on the separating composition part 40 again. Therefore, the reflected light of the vertically polarized light component is reflected by the separation and synthesis unit 40, and the reflected light is incident on the light receiving unit 50.

The light receiving unit 50 outputs an electrical signal corresponding to the light amount of the received reflected light. The RF and servo error generator 2 generates an RF signal RF, a focus error signal FE, a track error signal TE, and the like using the electrical signal output from the light receiver. The RF and servo error generator 2 then outputs the generated RF to the decoder 6 for reproduction. The decoder 6 here recovers the original form of data from the RF. In addition, the RF and servo error generator 2 outputs a control signal for data recording to the encoder 7. The encoder 7 encodes data to be recorded into recording pulses in a format required by the recording medium, and then records them on the recording medium via the optical pickup 1.

In addition, the RF and servo error generator 2 outputs the generated signal to the controller 3. The controller 90 receives a signal generated by the signal generator 2 and outputs a control signal. In this way, it is possible to control so that accurate data is recorded or reproduced in the recording and reproducing process.

Hereinafter, a method of determining the recording medium 80 and a recording / reproducing method in the recording / reproducing apparatus or the recording / reproducing apparatus whose position focused by the focus adjusting unit 30 as described above will be described in detail with reference to the drawings. .

According to the first preferred embodiment of the present invention, the recording medium 80 may be determined using a focus error signal (hereinafter referred to as FE) obtained during the focus scan of the recording medium 80. have. This will be described in detail with reference to FIGS. 8 to 11.

The FE is a signal representing the symmetry of the reflected light received by the light receiving unit 50 and may be calculated in an astigmatism manner. In the case of using the astigmatism method, the recording and reproducing apparatus may further include an astigmatism lens (not shown) on the optical path directed to the light receiving unit 50 of FIG.

8 illustrates a characteristic of an optical signal based on an astigmatism method, in which a cylindrical lens 45 may be used. The cylindrical lens 45 has a different focal length in a direction perpendicular to each other, which is called astigmatism. That is, two focuses are formed by light directed in different directions. Here, a point is formed between the two focus points having the same radius of light due to divergent light and converging light, and the light distribution section at this point is circular. An ellipse light having a long axis is formed in a vertical direction at a position closer to the cylindrical lens 45 and a horizontal direction at a focus at a far position among the two focuses. Therefore, when the light receiving unit 50 is located at the point where the circular light distribution is formed, it is possible to grasp the change in the position of the focus as the light distribution changes. That is, a signal as shown in FIG. 9 is formed depending on whether the focus of the light passing through the cylindrical lens 45 is correctly positioned in the recording layer. That is, when the focusing position of the lens unit 20 is farther than the recording layer (a), when it is close (c), and when it is located on the recording layer, the distribution is the same.

FE may be generated as follows, where a, b, c, and d are signals generated by the light receiver 50 of FIG. 7 and k1 corresponds to a proportional constant determined experimentally.

FE = k1 [(a + c)-(b + d)]

The FE formed as described above forms an S-shaped curve as shown in FIG. 10 when the focusing position is scanned from a position far from the recording layer to a position close to the recording layer. Here, when FE = 0, the focused position of the recording medium 80 corresponds to the recording layer. Therefore, information about the recording medium can be obtained by detecting a point where FE = 0 (zero-cross) in the FE detected during the focus scan process.

For example, as follows. A single layer and a multi-layer recording medium can be distinguished by counting a point at which FE = 0 detected in the focus scan process of the recording medium 80. In addition, the number of recording layers can be counted in a multi-layer recording medium.

In the focus scan process, a point at which FE = 0 is provided on the recording layer on the basis of the time point to obtain information about the thickness of the cover layer protecting the recording layer and the position of the recording layer. In addition, when a spacer layer is provided to space the recording layer, the thickness of the spacer layer may be measured by measuring an interval at which FE = 0 is repeated. In this manner, information on the number, thickness or position of the recording layer can be obtained. Based on this, the recording medium 80 can be determined.

A preferred embodiment of the recording medium discrimination method will be described in detail with reference to FIG. The recording medium 80 is loaded into the recording / reproducing apparatus (S11). Then, the recording and reproducing apparatus performs the focus scan by adjusting the focus adjusting unit 30 before reading the information contained in the recording medium 80 (S12). That is, the control unit 3 scans the light irradiated onto the recording medium 80 by moving the movable lens of the focus adjusting unit 30 in the optical axis direction.

In addition, the controller 3 detects a position at which FE = 0 along with the FE generated during the focus scan process (S13). On the basis of the detected contents, information on the number, thickness, position, etc. of the recording layer may be read to determine whether they correspond to the target recording medium required by the user or the recording / reproducing apparatus (S14).

According to the second preferred embodiment of the present invention, a tracking error signal (hereinafter referred to as "TE") or an RF signal (hereinafter referred to as "RF") obtained during the focus scan of the recording medium 80 Can be used to determine the recording medium 80. Since the method using the TE and the RF uses the same principle, the case of TE will be described in detail by way of example, and the case of using the same principle is not limited to the present embodiment.

The TE is a signal indicating the asymmetry of the reflected light as the light leaves the track of the recording medium 80. Tracks of the rotating recording medium 80 are caused by track shaking due to various causes. This track oscillation has not only the rotation frequency component of the recording medium 80 but also various high frequency components. At this time, even if there is a disturbance such as vibration or temperature change, the focused position to which light is irradiated follows the track shaking so that data can be recorded or reproduced on the track. It is then possible to drive the actuator in the opposite direction of the eccentric, i.e. out of the track, so that the pickup always follows the track. In this case, if the pickup leaves one track due to the eccentricity, one sinusoidal wave is output to the track error, so that the number of sinusoidal waves is output during one rotation of the recording medium, and the amount of eccentricity of the mounted recording medium is measured. Error signals appear in the form of sinusoids.

TE may be generated as follows, and a, b, c, and d are signals generated by the light receiver 50 of FIG. 7 and k2 corresponds to a proportional constant determined experimentally.

TE = k2 [(a + d)-(b + c)]

The TE formed as described above forms a sine wave which changes periodically as shown in FIG. 12 when the focusing position is scanned from a position far from the recording layer to a position close to the recording layer. This periodic change is because when the light irradiated onto the recording medium 80 is focused on the surface of the recording layer, the amount of reflected light is maximized, otherwise the amount of light is reduced. Therefore, as the position focused on the recording medium 80 is changed, a difference occurs in the amount of reflected light, thereby forming a sinusoidal wave that changes periodically.

That is, when focused on the surface of the recording layer, the amount of light of the signal formed by the reflected light has a maximum value 91 and gradually decreases as the position moves. Next, when light is irradiated onto the surface of the recording layer, the maximum value is again obtained. Therefore, the envelope 92 illustrated by connecting the peak points of the sinusoids can be used to grasp the change in the periodic signal and to determine the recording medium 80.

For example, as follows. A single layer and a multi-layer recording medium may be distinguished by counting a point at which the TE detected in the focus scan process of the recording medium 80 is the maximum value. In addition, the number of recording layers can be counted in a multi-layer recording medium.

In the focus scan process, a point having a maximum value of TE is provided on an upper portion of the recording layer based on a viewpoint to obtain information about a thickness of a cover layer protecting the recording layer and a position of the recording layer. In addition, when a spacer layer is provided to space the recording layer, the thickness of the spacer layer may be measured by measuring an interval in which the point having the maximum value of TE is repeated. In this manner, information on the number, thickness or position of the recording layer can be obtained. Based on this, the recording medium 80 can be determined.

A preferred embodiment of the recording medium discrimination method will be described in detail with reference to FIG. The recording medium 80 is loaded into the recording / reproducing apparatus (S21). Then, the recording and reproducing apparatus performs the focus scan by adjusting the focus adjusting unit 30 before reading the information contained in the recording medium 80 (S22). That is, the control unit 3 scans the light irradiated onto the recording medium 80 by moving the movable lens of the focus adjusting unit 30 in the optical axis direction.

In addition, the controller 3 detects a position having the maximum value in the envelope 92 of the TE generated in the focus scan process (S23). On the basis of the detected content, information on the number, thickness, position, etc. of the recording layer may be read to determine whether it corresponds to the target recording medium required by the user or the recording / reproducing apparatus (S24).

According to the third preferred embodiment of the present invention, the recording medium 80 can be determined using TE or RF together with the FE obtained in the process of focus scanning the recording medium 80. The method using the FE as described in the first embodiment may include an offset when the light irradiated to the recording medium 80 deviates from the track due to eccentricity or the like. Therefore, in the determination process using the FE, it is possible to check whether the offset is included by checking the TE or the RF together. For example, the method may further include checking whether the TE or the RF has the maximum value at the focused position of FE = 0 detected using the FE.

The recording and reproducing method of the preferred embodiment according to the present invention is as shown in FIG. When the recording medium 80 is loaded, the recording and reproducing apparatus determines the recording medium 80 in the same manner as described above prior to the step of reading data (S30). That is, information on the recording medium 80 is obtained based on the signal generated by the focus scan.

The recording and reproducing apparatus determines whether the loaded recording medium 80 corresponds to the target recording medium required by the user or the recording medium (S31). If it does not correspond to the target recording medium, it may be required to insert a new recording medium (S32). When the recording medium 80 corresponding to the target recording medium is loaded, a process of reading data or recording data including management information contained in the recording medium 80 is performed (S33). In this way, the time required for reading the management information contained in the recording medium 80 can be shortened, and the recording medium 80 can be determined and recorded and reproduced.

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 above-described effects can be expected in the recording / reproducing apparatus and method and the method of discriminating the recording medium according to the present invention as described above in detail.

That is, there is an advantage that the position of the light irradiated onto the recording medium is varied by adjusting the focus adjuster provided separately from the lens portion.

In addition, there is an advantage in that the number of recording layers included in the recording medium and the position thereof can be grasped, and control can be made to change and maintain the position where the light is irradiated to the desired recording layer.

In addition, there is an advantage that the recording medium can be determined without reading the management information contained in the recording medium.

Claims (15)

A lens unit for collecting or irradiating light emitted from the light source; A focus adjuster provided on the path of the light to vary the position of the focus on which the light is irradiated onto the recording medium; A driving unit which scans a recording medium by adjusting the focus adjusting unit; A light receiving unit for receiving the light reflected on the recording medium and generating a signal; And And a control unit for determining the recording medium by using the signal generated in the scanning process. The method of claim 1, wherein the focus adjustment unit, And at least one adjustable lens for changing the path of the light. The method of claim 2, wherein the focus adjustment unit, And a second lens fixed in position and a second lens movable in the optical axis direction. The method of claim 1, wherein the control unit, And information on the number, thickness, or position of the recording layer of the recording medium, in response to the changing periodicity of the signal. The method of claim 1, wherein the control unit, And the focus position is determined as the position of the recording layer when the value of the focus error signal (FE) becomes zero. The method of claim 5, wherein the focus error signal FE, A recording and reproducing apparatus, characterized by a signal representing the symmetry of light formed by the astigmatism method. The method of claim 1, wherein the control unit, And the focused position is determined as the position of the recording layer when the value of RF or TE becomes maximum. The method of claim 1, wherein the control unit, And when the value of the focus error signal (FE) becomes 0 and the value of RF or TE becomes maximum, the focused position is determined as the position of the recording layer. A recording and reproducing apparatus using a near field, A near field forming lens provided with an objective lens and configured to form a near field at a distance from the recording medium; A focus adjuster provided on a path of light emitted from the light source, the focus adjuster configured to vary a position of a focus at which light is irradiated onto the recording medium; A driving unit which scans a recording medium by adjusting the focus adjusting unit; A light receiving unit for receiving the light reflected on the recording medium and generating a signal; And And a control unit for determining the recording medium by using the signal generated in the scanning process. The method of claim 8, wherein the control unit, And information on the number, thickness, or position of the recording layer of the recording medium, corresponding to the periodicity of the signal generated during the scanning process. In a recording / reproducing apparatus having a lens for forming a near field and maintaining a distance between the recording medium and a focus adjusting portion provided on the optical path to change the position of the focus, And adjusting the focus adjuster to scan the focus of the recording medium, and determine the structure of the recording medium by changing the signal generated during the scanning process. The method of claim 11, wherein the determination method, And determining the number, thickness, or position of the recording layer of the recording medium in accordance with the periodicity of the signal change. The method of claim 12, wherein the determining method, And counting the number of times the value of the focus error signal becomes '0'. The method of claim 12, wherein the determining method, A counting method of a recording medium, characterized in that the number of times the value of the RF (RF) signal or the track error signal becomes maximum is counted. A method of recording and reproducing a recording medium in a near field recording and reproducing apparatus, the method comprising: (a) adjusting the focus adjuster to scan the focus; (b) determining the structure of the recording medium by using the change of the signal generated in the scanning process; (c) requesting insertion of a new recording medium if the recording medium does not correspond to a target recording medium.

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