KR20100067723A - The method for recording and reproducing of the recording medium and the apparatus for the same - Google Patents

Abstract

PURPOSE: Recording/reproducing method and device of a recording medium are provided to accurately and precisely control a recording medium and a recording/reproducing device by overcoming the distortion of a servo signal and servo instability. CONSTITUTION: A recording/reproducing method a recording medium comprises next steps. Light for the recording/reproducing of data is illuminated from a pick-up(10) to a recording medium. The illuminated light blocks the specific area of the light reflected or diffracted from the recording media. The distance between the pick-up and the recording media is controlled using the blocked light. The specific area of the blocked light corresponds to the area within the predetermined incident angle of the light illuminated to the recording media. The predetermined incident angle of the light illuminated corresponds to a critical angle. The critical angle corresponds to the incident angle at which the light incoming to the recording media from the pick-up is totally reflected from the recording media.

Description

 Recording method and recording and reproducing apparatus of the recording medium {THE METHOD FOR RECORDING AND REPRODUCING OF THE RECORDING MEDIUM AND THE APPARATUS FOR THE SAME}

The present invention relates to a recording and reproducing method and a recording and reproducing apparatus of a recording medium, and more particularly, to a method and apparatus for controlling a pickup unit and a recording medium in recording and reproducing of a recording medium.

Recently, various recording media have appeared due to the rapid development of technology. Such recording media include CD (Compact Disc), DVD (Digial Versatile Disc). In addition, BD (Blu-ray Disc), Near Field Recording (NFR), and the like are the next generation recording media that have significantly increased capacity than the above-described CD and DVD. The next generation recording media described above use a light source with a shorter wavelength and an optical system having a high numerical aperture to increase the capacity. In addition, as the capacity of the recording medium increases, a more precise control system is required, and research and development for this purpose are being conducted.

An object of the present invention is to provide a method and apparatus for precise control of a pickup unit and a recording medium in controlling the recording medium and the recording and reproducing apparatus.

In order to solve the above problems, irradiating light from the pickup unit to the recording medium for recording and reproducing data, blocking a specific area of the light reflected or diffracted from the recording medium, and using the blocked light. And controlling the distance between the recording medium and the pickup unit.

In addition, the specific region of the blocked light provides a method for recording and reproducing a recording medium corresponding to an area within a predetermined angle of incidence of light irradiated onto the recording medium.

In addition, the predetermined incident angle of the irradiated light provides a method of recording and reproducing the recording medium corresponding to the critical angle.

In addition, the critical angle provides a method for recording and reproducing a recording medium in which light incident on the recording medium from the pickup unit is an incident angle at which total reflection is made on the recording medium.

In addition, the present invention provides a method of recording and reproducing a recording medium, further comprising forming a signal using the blocked light.

Further, the signal provides a method of recording and reproducing a recording medium which is a gap error signal.

The recording and reproducing method of the recording medium also provides a recording and reproducing method of the recording medium using a near field.

According to another aspect of the present invention, the pickup unit for irradiating light to the recording medium and blocking a specific area of light reflected or diffracted from the recording medium and controlling the distance between the recording medium and the pickup unit using the blocked light A recording and reproducing apparatus of a recording medium including a control unit is provided.

Further, the pickup unit provides a recording / playback apparatus of a recording medium including an optical blocker for blocking a specific area of light.

Further, the specific region of the blocked light provides a recording / reproducing apparatus of the recording medium corresponding to an area within a predetermined angle of incidence of the light irradiated onto the recording medium.

In addition, the predetermined incident angle of the irradiated light provides a recording / reproducing apparatus of the recording medium corresponding to the critical angle.

In addition, the critical angle provides an apparatus for recording and reproducing a recording medium, the incident angle of which light incident on the recording medium from the pickup unit is totally reflected on the recording medium.

In addition, the present invention provides a recording and reproducing apparatus of a recording medium, further comprising a signal generator for forming a signal using the blocked light.

Further, the signal provides a recording / playback apparatus of a recording medium which is a gap error signal.

The recording and reproducing method of the recording medium also provides a recording and reproducing apparatus for the recording medium using a near field.

The recording and reproducing method of the recording medium and the recording and reproducing apparatus according to the present invention are for precisely controlling the position of the recording and reproducing apparatus with respect to the recording medium, thereby preventing the distortion of the servo signal and improving the quality of the servo signal.

In addition, by solving the servo instability, it is possible to control the recording medium and the recording and reproducing apparatus more accurately and precisely.

Hereinafter, preferred embodiments of a recording / playback method and a recording / playback apparatus of a recording medium according to the present invention will be described in detail with reference to the accompanying drawings.

In addition, the terminology used in the present invention was selected as a general term widely used as possible, but in some cases, the term is arbitrarily selected by the applicant, and in this case, since the meaning is described in detail in the description of the present invention, the term is simply a term. It is to be understood that the present invention is to be understood as meanings of terms other than names.

In this regard, in the present invention, the recording medium means any medium in which data is recorded or can be recorded, and includes all media regardless of a recording method such as a disk and a magnetic tape. Hereinafter, the present invention will be described using a disk, in particular, a near field recording medium as a recording medium for convenience of explanation, but it will be apparent that the technical concept of the present invention is equally applicable to other recording media.

1 is a block diagram showing the configuration of a recording / playback apparatus according to an embodiment of the present invention.

As shown in FIG. 1, the recording and reproducing apparatus according to the present invention includes a pickup section 10 and a control section 50. As shown in FIG. In addition, the recording and reproducing apparatus includes a servo unit 80 including a signal generator 30, a controller 50, a spindle servo 70, and a gap servo 40, a sled motor 20, and a spindle motor 60. ) And a host (not shown).

The pickup unit 10 irradiates light to the recording medium, and collects light reflected or diffracted from the recording medium to generate a signal. Position control of the pickup section 10 is essential for accurate recording or reproduction of the recording medium. If the position between the recording medium and the pickup section 10 is not accurately controlled, it is also difficult to read accurate information from the recording medium and to record accurate information. For this reason, accurate position signal information for position control between the pickup section 10 and the recording medium is required. For example, signal information regarding a gap Gap, which is a vertical distance between the recording medium and the pickup unit 10, signal information about whether the pickup unit 10 is horizontally balanced on the track of the recording medium, and pickup And the signal information about whether the unit 10 is inclined relative to the recording medium.

A detailed configuration of the pickup unit 10 will be described later in detail with reference to FIG. 2.

The signal generator 30 uses a signal generated by the pickup unit 10 to track a playback signal (RF signal), a gap error signal (GES) and tracking required for controlling the pickup unit 10 and the recording medium. Generate an error signal (TES, Tracking Error Signal). As mentioned above, the gap error signal is a signal indicating the vertical distance between the recording medium and the pickup section 10, and the tracking error signal is a signal indicating the position on the track between the recording medium and the pickup section.

The controller receives the signal generated by the signal generator and generates a control signal or a drive signal. For example, by receiving the gap error signal generated by the signal generator, it is possible to generate a control signal for controlling the vertical distance between the recording medium and the pickup.

The gap servo 40 drives an actuator (not shown) according to the gap control signal information of the pickup unit and the recording medium detected by the control unit via a gap error signal GES, thereby controlling the gap between the pickup unit and the recording medium in real time. do. The spindle servo 70 controls the spindle motor 60 to rotate the recording medium according to the rotation speed control signal information of the recording medium detected by the control unit 50 through the reproduction signal (RF signal). The sled motor 20 is driven by a sled servo (not shown) and moves the pickup section 10 in the radial direction.

2 shows a pickup section 10 of a recording / playback apparatus according to an embodiment of the present invention. 2 will be described in detail with reference to the flow of signals based on the traveling direction of the light emitted from the light source inside the pickup unit 10.

Pick-up unit 10 according to the present invention is a light source 110, the first separation unit 12, the second separation unit 130, the lens unit 140, the first light receiving unit 170 and the second light receiving unit ( 180). The pickup unit 10 according to the present invention may include a collimator lens 115. The collimator lens 115 serves to convert incident light into parallel light.

In the embodiment shown in FIG. 2, the light emitted from the light source 110 is incident on the first separation synthesis unit 120, partly reflected and partly passed through and incident on the second separation synthesis unit 130. The second separation synthesis unit 130 passes the vertical polarization component and reflects the horizontal polarization component in the linearly polarized light. As the first separation synthesis unit 120, a non-polarized beam splitter (NBS) may be used. Obviously, the roles of the first separation synthesis unit 120 and the second separation synthesis unit 130 may be changed. In addition, a polarization conversion surface (not shown) may be included on the path of the light passing through the second separation synthesis unit 130.

Light passing through the second separating synthesis unit 130 is incident to the lens unit 140. Light incident on the objective lens 55 of the lens unit 140 passes through the near field forming lens 65 to form a dissipated wave. Specifically, light incident on the near field forming lens 65 at an angle greater than or equal to a critical angle is totally reflected on the surface of the lens 65 and the surface of the recording medium 100. Light incident on the near field forming lens 65 at an angle equal to or less than the critical angle is reflected on the recording layer 75 of the recording medium. The dissipation wave generated in this process reaches the recording layer 75 of the recording medium to perform recording and reproduction.

The light reflected from the recording medium 100 is incident to the second separation synthesis unit 130 through the lens unit 140 again. The polarization conversion surface may be provided on a path incident to the second separation synthesis unit 130. The polarization converting surface converts the polarization direction of the light incident on the recording medium and the reflected light. Accordingly, the light incident only by passing the horizontal polarization component by the second separation synthesis unit 130 has the vertical polarization component when it is reflected on the recording medium and is incident on the second separation synthesis unit 130 again. Therefore, the reflected light of the vertical polarization component is reflected by the second separation synthesis unit 130, and the reflected light is incident on the second light receiving unit 180. The light blocking unit 190 may be included between the second separation synthesis unit 130 and the second light receiving unit 180. The light blocking unit 190 blocks a specific region of the light incident from the second separating synthesis unit 130 to inject only the light of the specific region into the second light receiving unit 180. The second separation synthesis unit 130 may include a light blocking unit 190 for blocking light of a specific region. Alternatively, the second light receiving unit 180 may include a light blocking unit 190 to block light in a specific region. The role and necessity of the light blocking unit 190 will be described in detail later with reference to FIG. 3.

A portion of the reflected light incident on the second separation synthesis unit 130 has a horizontal polarization component due to the distortion in the polarization direction, and passes through the second separation synthesis unit 130. The reflected light passes through the first separation synthesis unit 120. In addition, the first separation synthesis unit 120 passes a portion of the incident light and reflects the portion. The light reflected by the first separating synthesis unit 120 is incident to the first light receiving unit 170. In addition, the light blocking unit 190 may be included between the first separation combining unit 120 and the first light receiving unit 170. Obviously, the first separation combining unit 120 or the first light receiving unit 170 may include a light blocking unit 190 for blocking light of a specific region.

The light receiving units 170 and 180 receive the amount of light that has passed through the separation synthesizer 120 and 130 and output an electrical signal corresponding to the amount of light. The light receivers 170 and 180 are configured in multiple division areas. It may be composed of two photodetecting elements (PDA, PDB) that are divided in a specific division, for example, two divisions in a signal track direction or a radial direction of the recording medium 100. Here, each of the photodetectors PDA and PDB generates electrical signals a and b proportional to the amount of light received. Alternatively, the light receiving units 170 and 180 may be configured with four photodetectors (PDA, PDB, PDC, PDD) divided into four in the signal track direction and the radial direction of the recording medium 100. The photodetecting elements constituting the light receiving units 170 and 180 are not limited to this embodiment, and various modifications and selections may be made as necessary.

The role of the light blocking unit 190 mentioned above will be described in detail with reference to FIGS. 3 to 5. As an exemplary embodiment of the present invention, the gap error signal GES will be described based on the present invention. However, the present invention is not limited thereto, and it is obvious that the present invention is applicable to all error signals or servo signals generated by the signal generator 30.

The four photodetectors constituting the aforementioned second light receiver 180 output electrical signals a, b, c, and d corresponding to the amount of light received. In this case, the gap error signal GES is generated by adding all signals output from the photodetecting elements constituting the second light receiver 180. The gap error signal GES generated as described above is represented as follows.

Since the gap error signal GES corresponds to the sum of electrical signals corresponding to the amount of light, the gap error signal GES is proportional to the amount of reflected light received by the second light receiver 180.

Meanwhile, referring to FIG. 3, when light incident through the pickup unit 10 is incident at an angle of incidence greater than or equal to the critical angle, the lens unit 140, specifically, the near field forming lens 65 or the recording medium 100, as in the A region. ) Is totally reflected. In this process, the totally reflected light is used to generate error signals or servo signals including a gap error signal (GES). Further, light incident at an angle of incidence below the critical angle, that is, light in the region B, is reflected by the recording layer 75 of the recording medium. The dissipation wave generated in this process reaches the recording layer 75 of the recording medium to perform recording and reproduction of the recording medium. That is, the gap error signal GES is generated using only the totally reflected light of the area A and the vertical distance between the pickup unit 10 and the recording medium 100 is determined as the sum of the total amount of reflected light of the area A.

However, there may occur a case where the light incident to the area B or less than the critical angle is reflected by the recording layer 75 of the recording medium and received by the light receiving units 170 and 180. In this case, the light receiving units 170 and 180 recognize the light generated in the B area as the totally reflected light in the A area, calculate the sum of the light amounts, and reflect the light in the gap error signal GES. This makes it difficult to accurately measure the gap error signal GES value, resulting in distortion of the signal. In addition, an incorrect gap error signal GES value makes it difficult for the controller 50 to accurately control the distance between the pickup unit 10 and the recording medium 100.

For this reason, the light blocking unit 190 serves to block the light corresponding to the B region between the separation synthesis unit 120 and 130 and the light receiving units 170 and 180. Specifically, light incident at an angle of incidence below the critical angle blocks light reflected from the recording medium 100 so that only the amount of light above the critical angle can be summed. In this case, the light blocking unit 190 may be included in the separation composition parts 120 and 130. In addition, the light receiving units 170 and 180 may include the light blocking unit 190.

The light blocking unit 190 may employ all of the basic methods of blocking light. For example, an opaque film may be attached so as to correspond to an area below the critical angle. The area below the critical angle may be specified by those skilled in the art in various ways. For example, it may be possible to calculate the radius from the center of light by calculating the width and the critical angle of the lens portion.

4 and 5 illustrate regions of light received by the light receiving unit.

Referring to FIG. 4, it can be seen that the light totally reflected by the region A is received as α, and the signal reflected from the recording layer of the recording medium in the region B is received as β. In the case of a gap error signal, all the received amounts of light are added together to determine the signal value by adding the value of α + β. Therefore, it is difficult to calculate an accurate gap error signal and distortion of the gap error signal occurs.

Referring to FIG. 5, it can be seen that the total reflection signal by region A is received as γ, and the region δ is not receiving light by the light blocking unit. By receiving only γ required for the gap error signal, an accurate gap error signal can be derived.

6 shows a pickup section of a recording / playback apparatus according to another embodiment of the present invention. Light source 110, collimator lens CL, first separation synthesis unit 120, second separation synthesis unit 130, quarter wave plate (QWP), beam expander, lens The unit 140 may include a first light receiving unit 170, a second light receiving unit 180, and a light blocking unit 190. The description of the aforementioned components will be omitted. In the present invention, a beam expander may serve to expand light incident from a light source. In addition, QWP serves to change the polarization direction. For example, vertical polarization can be converted to horizontal polarization or horizontal polarization to vertical polarization. Right Angle Prism is used to change the light path. In addition, a right angle mirror may be used instead of the right prism to change the optical path.

In addition, the light receiving units 170 and 180 of the present invention may include sensor lenses SL and 150 and 160. The sensor lens SL collects light received by the light receiving element. Here, the focal length of the sensor lens is an element that can vary depending on the configuration of the recording device. Depending on the focal length of the sensor lens, the arrangement distance of the light receiving parts 170 and 180 may also vary. The light receiving units 170 and 180 of the present invention may include the light blocking unit 190. The light blocking unit 190 may block a specific area of incident light. For example, the light passing through the second separating synthesis unit 130 is incident on the sensor lenses 152 and 153, respectively. In this case, the light passing through the light blocking unit 190 is received by the light receiving units 170 and 180 while blocking light in a specific region. As mentioned above, the light passing through the second separation synthesis unit 130 may be used to detect the gap error signal GES or the like. In addition, it will be apparent that the number of divided regions of the light receiving element used in receiving the light passing through the second separation synthesis unit 130 may be set in various ways according to the characteristics and purposes of the recording / reproducing apparatus.

7 is a flowchart illustrating a recording / reproducing method of a recording medium according to an embodiment of the present invention.

Light is irradiated to the recording medium 100 from the pickup unit 10 (S10). The light may be selected according to the type of the recording medium 100. The light reflected or diffracted from the recording medium 100 is split in the second separation synthesis unit 130 (S20). At this time, the type of light to be divided may vary depending on the recording / playback apparatus. One of the divided lights is received by the light receiving unit 180 while the specific region is blocked by passing through the light blocking unit 190 (S30). Obviously, the light may be received by the light receiving unit 180 while the light is blocked in the second separating synthesis unit 130 without the light blocking unit 190. In addition, the light receiving unit 180 may be configured to block light in a specific region. The light receiver 180 may include two or four photo detectors. A gap error signal is generated using the sum of the amounts of light from which light in a specific region is removed (S40). The controller 10 controls the distance between the pickup unit and the recording medium by using the gap error signal GES (S50).

In the present invention, the gap error signal GES is described as an embodiment, but the present invention is not limited thereto, and it is obvious to introduce a light blocking unit to use only light in a specific region due to characteristics of various signals. For example, the reproduction signal (RF signal) may be used for a method of blocking light above a critical angle.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present invention.

In addition, the technical scope of the present invention should not be limited to the contents described in the embodiments, but should be defined by the claims.

1 is a block diagram showing the configuration of a recording / playback apparatus according to an embodiment of the present invention.

2 shows a pickup section of a recording / playback apparatus according to an embodiment of the present invention.

3 illustrates a form of light incident on a recording medium according to an embodiment of the present invention.

4 to 5 illustrate regions of light received by the light receiving unit according to the exemplary embodiment of the present invention.

6 shows a pickup section of a recording / playback apparatus according to another embodiment of the present invention.

7 is a flowchart illustrating a recording / reproducing method of a recording medium according to an embodiment of the present invention.

Claims (15)

Irradiating light from the pickup section to the recording medium for recording and reproducing the data; Blocking a specific area of light from which the irradiated light is reflected or diffracted from the recording medium; And And controlling the distance between the recording medium and the pickup unit using the blocked light. The method of claim 1, And the specific area of the blocked light corresponds to an area within a predetermined angle of incidence of light irradiated to the recording medium. The method of claim 2, And a predetermined angle of incidence of the irradiated light corresponds to a critical angle. The method of claim 3, wherein And the threshold angle is an incident angle at which light incident on the recording medium from the pickup unit is totally reflected on the recording medium. The method of claim 1, And forming a signal using the blocked light. The method of claim 5, And the signal is a gap error signal. 7. The method according to any one of claims 1 to 6, The recording and reproducing method of the recording medium is a recording and reproducing method of a recording medium using a near field. A pickup unit for irradiating light to the recording medium and blocking a specific area of light reflected or diffracted from the recording medium; And And a control unit controlling a distance between the recording medium and the pickup unit by using the blocked light. The method of claim 8, And the pick-up section includes a light blocking section for blocking a specific area of the light. The method of claim 8, And the specific area of the blocked light corresponds to an area within a predetermined angle of incidence of light irradiated onto the recording medium. The method of claim 10, And a predetermined angle of incidence of the irradiated light corresponds to a critical angle. The method of claim 11, And the threshold angle is an incident angle at which light incident on the recording medium from the pickup unit is totally reflected on the recording medium. The method of claim 1, And a signal generator for forming a signal using the blocked light. The method of claim 13, And the signal is a gap error signal. The method according to any one of claims 8 to 14, The recording and reproducing method of the recording medium is a recording and reproducing apparatus of a recording medium using a near field.

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