KR100200827B1 - Information recording and reproducing apparatus and the method thereof for optical disc - Google Patents

Abstract

The present invention relates to an information recording apparatus and method for an optical disk, such as a compact disk, a magneto-optical disk, or a laser disk for video, which is currently commercially available.

That is, the information recording apparatus and method of the optical disk according to the present invention include an optical disk for measuring the eccentricity for tracking servo of the recording disk, i.e., the master disk, and an optical head for eccentric movement according to the information contained in the track of the optical disk; A vibration mirror is provided at the front end of the recording objective lens so as to correct this error by using information about the tracking error detected by the optical system and the servo optical system, and the amount of eccentricity of the recording light irradiated on the master disk is lowered. By correcting the track of the measuring disk so that it does not deviate, the information recording process can be performed without the need for expensive equipment such as air bearings or ultra-precision linear stages or a work room, and the spindle motor can be reduced in price. Rotation and linear motor translation are always optical Since sensing control by reducing the defects due to wear of the precision mechanism it has a large effect on productivity improvement.

Description

Information recording apparatus and method of optical disc

1 is a process diagram schematically showing a typical manufacturing process of a conventional optical disk substrate,

2 is a block diagram illustrating an optical recording apparatus of a conventional optical disk,

3 is a schematic block diagram of an information recording apparatus of an optical disk according to the present invention,

4 is an excerpt cross-sectional view of the features of FIG.

5 is an excerpt perspective view of an optical disk according to the present invention,

6 is a cross-sectional view of the mast disk and sensor disk support,

7 is an explanatory diagram of the servo principle of the objective lens using the sensor disk when recording information on the mast disk.

* Explanation of symbols for main parts of the drawings

1 substrate 2 photoresist film

3: metal film 4: plating film

5: metal substrate 6: stamper

7: substrate 11: laser diode

12 light modulator 13 reflector

14 dichroic mirror 15 objective lens

16 actuator 17 optical system for focus servo

18: servo circuit 19: master disk

20: spindle motor 21: linear motor

211: position sensor 22: computer control unit

23: drive circuit 24: information device

31 laser diode 32 light modulator

33: reflector 34: dichroic mirror

35 objective lens 36 actuator

37 optical system for focus servo 38 servo circuit

39: master disk 40: sensor disk

41: Feet 42: Shield

43: reflecting film 45: sensor objective lens

46 sensor objective lens actuator 47 master disk eccentricity measuring unit

48: vibrating mirror 49: servo circuit

50: spindle motor 51: linear motor

52: computer control unit 53: drive circuit

54 information device 55 servo optical system

56: sensor optical system 57: dichroic mirror for the sensor

58: blocking filter 59: focusing lens

60: two-part photodetector 65: hub

66: spacer 67: centering jig

68: disc fixing jig

The present invention relates to an information recording apparatus and method for an optical disk, such as a compact disk, a magneto-optical disk, or a laser disk for video, which is currently commercially available.

For example, a reproduction-only optical disc containing optically reproducible information. In addition to the compact disc or laser disc mentioned above, a CD ROM, a video ROM and a video signal containing various types of character information such as a dictionary and a publication are included. There are compact video discs and video single discs which are distributed and recorded in a certain ratio.

These disks all have a reflective film to which light is reflected, and the reflective film contains information formed in an array of concave and minute countless pit formed along a spiral track. As the concave pit formed in the reflective film is irradiated with light to the disk containing the information, the light is reflected brightly in the reflective film without the pit and darkly reflected in the pit so that the amount of light varies according to the arrangement of the pit. Reflect. Therefore, the information can be reproduced by detecting an electrical signal from the modulated light.

FIG. 1 is a typical manufacturing process diagram of a conventional optical disk, in which the master disk manufacturing step (A), the stamper manufacturing step (B), and the substrate forming step (C) are performed in this order. It can be divided largely.

In the master disk manufacturing step (A), the photosensitive agent 2 is applied to the glass substrate 1 polished to an ultra precision with a thickness of 0.12 μm, and the contents to be recorded thereon are recorded. Recording is to partially expose a photoresist film applied to the glass substrate by irradiating a laser beam modulated according to the desired information using a device called a mastering machine.

At this time, the applied photosensitive agent 2 becomes a photoresist excellent in sensitivity with respect to the recording laser wavelength.

In the next stamper fabrication step (B), the metal film 3 is deposited thinly on the master disk 19, and the metal film such as nickel is again electroplated on the metal film, and then the plating film 4 is separated to separate a metal substrate. Attach to (5) to complete the stamp.

Subsequently, the substrate forming process (C) heat-injects thermoplastic resins such as polycarbonate (PC), PMMA, and APO to the stamp manufactured as described above, and makes a substrate. After pressing, ultraviolet rays are irradiated and cured, and then separated to prepare a substrate of an optical disk.

On the other hand, the configuration and operation of the optical recording apparatus for mast disk recording as shown in Fig. 2 are as follows.

At the time of information recording, a laser beam generated by the recording laser 11 which is continuously oscillated is reflected by the reflector 13 through the optical modulator 12 and is incident on the dichroic mirror 14. This beam passes through a dichroic mirror 14 that transmits light at the wavelength of the recording laser beam 11 and is then focused by the objective lens 15 to focus on the photoresist 2 on the master disk 19. . In this case, in order for the focal point to be always located on the photoresist surface, a device capable of detecting and correcting the distance between the objective lens 15 and the photoresist surface is required. For this purpose, a focus servo is provided on the side of the dichroic mirror 15. The optical system 17 is provided, and the servo laser beam emitted from the optical system is reflected by the dichroic mirror 15 and passes through the objective lens 16 to focus on the photoresist surface. The error signal generated by the servo optical system 17 is amplified by the servo circuit and applied to the actuator 16 of the objective lens 15 to drive the objective lens 15 up and down to maintain the focal length.

And during this recording process, the master disk 19 rotates while being mounted on the spindle motor 20, and this spindle motor 20 is installed on the linear motor 21. As shown in FIG. Since the linear motor 21 moves in a straight line, a spiral recording track is formed on the master disk 19.

In order to maintain the precision of the rotation of the spindle motor 20, the rotation shaft is generally supported by an air bearing, and a rotation sensing encoder is mounted in the spindle motor to recognize the amount of rotation.

In addition, in order to control the linear movement of the linear motor 21 and the rotational speed of the master disk 19, as shown in FIG. 2, the control unit 22 uses the signal of the position sensor 211 at present. The master disc 19 is moved horizontally by reading the position of the position and driving the linear motor 21 at a speed corresponding to the position. This speed corresponds to the speed of one track pitch per rotation in the case of the angular speed optical disk, and the speed inversely proportional to the radius of the current position in the case of the optical speed disk. Since the distance between the track centers of the optical discs currently used, that is, the track pitch is about 1.6 μm and the track width is about 0.4 μm, is very fine, the precision of about 0.05 μm is maintained for such track processing. In addition, the position detection sensor 211 is attached to detect the progress of the linear motor.

The signals of the rotation detection encoder and the position detection sensor 211 are input to the computer control unit 22 and used to drive the spindle motor 20 and the linear motor 21. However, because the rotation and linear motion of the master disk 17 requires strict precision and control, such a mastering machine (aka cutting machine) is composed of components such as a very precise spindle motor, a linear motor, a position sensor, and precision instruments. It is not only expensive but also difficult to maintain and repair.

In order to produce a reproducing optical disc using the method described above, the environmental management such as fine dust, temperature, humidity, vibration, etc. should be very strict. Therefore, expensive facilities, such as a large clean room is required, so improvement is required.

In addition, since the damage of the stamper due to the contact between the stamper and the substrate material occurs in the process of forming the substrate (7), there is a limit to the number of substrates that can be manufactured with a single stamper, and improvement is required.

The present invention simplifies a complicated process in the production process of an optical disc, and thus, does not require a large clean room, and has a low-cost recording optical disc with no quantitative limitation in reproduction. It is an object of the present invention to provide an information recording apparatus and method for an optical disc which can produce contents on the fly.

In order to achieve the above object, the information recording apparatus of the optical disk according to the present invention includes a recording optical head, a spindle motor and a linear motor for rotating and shifting the optical disk, respectively, an optical modulator of the optical head and the An optical disc information recording apparatus comprising drive means for driving two motors under control of a control means, the optical disc information recording apparatus comprising: an eccentric amount measuring optical disc for measuring an eccentricity amount caused by the translational movement of the optical disc; Tracking means for causing the recording optical head to record information along a predetermined track of the optical disk for measuring the eccentricity;

And fixing means for fixing the eccentric amount measuring disk and the optical disk to be rotatable on the spindle motor.

In the present invention, the eccentricity measuring disk is preferably installed to have a distance of 0.3mm with the optical disk,

The tracking means preferably includes an eccentricity measuring optical head 47 for following the track of the eccentricity measuring disk and light reflecting means rotatably provided at the front end of the recording objective lens.

In addition, the information recording method of the optical disk by the above apparatus comprises the steps of: irradiating the recording light emitted from the light source onto the recording optical disk through the recording objective lens; A light detecting step of detecting the degree of eccentricity in which the focus of the irradiated light is off the track of the eccentricity measuring disk;

Calculating an eccentricity of the recording light from the detected light amount;

And servoing the translational motion of the recording light incident on the recording objective lens according to the calculated eccentricity information.

An information recording apparatus and method for an optical disc according to the present invention will be described below with reference to the drawings.

3 is a schematic block diagram of an information recording apparatus of an optical disk according to the present invention. The configuration is as follows.

An optical modulator 32 and a reflector 33 are provided on the optical path of the beam oscillated by the optical recording laser diode 31 installed horizontally, and a dichroic mirror 34 is provided below the reflector 33. The dichroic mirror 34 selects and uses a property of reflecting light of an optical recording laser wavelength, and a vibrating mirror driven by an actuator on the optical path of the laser beam reflected laterally from the dichroic mirror 34 ( 48) is installed at an angle of 45 degrees, and the objective lens is installed on the optical path of the laser beam reflected from the vibration mirror 48, but the objective lens 35 is installed in the actuator capable of vertical movement.

On the other hand, the servo optical cradle 37 is provided behind the dichroic mirror 34, wherein the servo laser beam emitted through the dichroic mirror 34 passes through the dichroic mirror 34 as it is and is the same optical path as that of the optical recording laser beam. Through the focus is formed on the surface of the master disk (39).

In addition, an optical head 47 for measuring an eccentric amount for detecting an oscillation in a radial direction, that is, an amount of eccentricity, is installed below the master disc 39. In addition, a kind of optical disk (hereinafter referred to as a sensor disk 40) specially manufactured to measure the amount of eccentricity is installed below the master disk 39 so as to have a distance of about 0.3 mm from the lower surface of the master disk 39. The spindle motor 50 and the linear motor 51 are provided for the linear motion in the radial direction for the rotation drive of the master disk 39 and the sensor disk 40.

Here, in particular, the installation state of the optical head 47 for measuring the eccentricity, as shown in FIG. 3, the objective lens of the optical head 47 for measuring the eccentricity along the optical axis of the objective lens 35 for optical recording (hereinafter, referred to as a sensor). It is called an objective lens, and it is attached to an instrument with an optical recording objective lens so that the optical axes of 45) coincide. The configuration of the optical head 47 for measuring the eccentricity is the focusing and tracking error seen in a general optical head. As shown in FIG. 4, a detection optical system (referred to as a sensor optical system) is provided along the optical axis of the sensor objective lens 45, and light of the servo laser wavelength is provided between the sensor objective lens 45 and the sensor optical system. A dichroic mirror 34 for a sensor is provided to reflect and transmit light of the laser wavelength of the sensor optical system, but the optical wave is recorded on the optical path where the servo laser beam is reflected by the dichroic mirror 34 for the sensor. Two-segment photodetector 60, which blocks light of the field and transmits the light of the servo optical system 37, and a focusing lens 59 in order, and is divided into two vertically at the focus of the lens. It is installed so that the focus by the focusing lens 59 of the laser beam for servo is installed in the center of the two-segment photodetector 60.

Meanwhile, as shown in FIG. 5, the sensor disk 40 is manufactured to have a constant track-to-track spacing on the upper surface, and digital information about the radius and rotation angle in the sensor disk 40 along the track. The information is recorded in the form of a pit 41 which is protruded to a constant height and modulated in length as in a general compact disc, and a reflective film 43 having a constant reflectance and transmittance is formed on the pit surface. The protective film 42 is formed to protect the reflective film. The sensor disk 40 may be manufactured by a general compact disk manufacturing process. In addition, the sensor disk 40 is installed under the master disk 39 by the instruments as shown in FIG. Referring to FIG. 6, the hub 65, which is threaded at the lower center of the master disk 39, is attached to the lower center of the master disk 39, and the outer diameter of the hub 65 is equal to the inner diameter of the sensor disk 40. The hub 65 is installed to be inserted into the center hole of the sensor disk 40, but the signal surface of the sensor disk 40 due to contact between the master disk 39 and the sensor disk 40 is prevented from being damaged. In order to install the spacer and the lower part of the sensor disk 40 as shown in Figure 6, it has a size that can hold the sensor disk 40, but the lower part has a screw hole to insert a screw from the lower side of the master disk There is a centering jig 67 for keeping the 39 and the sensor disk 40 in close contact with each other, and the centering jig 67 is made of a magnetic material to be fixed to the iron disk fixing jig of the spindle motor 50 by magnetic force. Can be .

The operation principle of the optical disk recording apparatus having such a configuration is as follows.

As shown in FIG. 3, the optical controller 47 for the sensor is moved by the computer control unit 52 and the drive circuit 53 by moving the recording objective lens 35 to the innermost angle of the master disk 39. The drive of the servo optical system 55 is started. The sensor optical head 47 generates an electric signal according to the amount of light of the laser beam reflected from the pit 41 of the sensor disk 40, and the computer control unit 52 analyzes the electric signal to record the optical head. The positional information of the objective lens 35 and the rotational speed control signal of the master disk 39 are read. The computer controller 52 analyzes the positional information and the rotational speed control signal and controls the rotational speed of the spindle motor 50 using the drive circuit 53 according to the position of the recording optical head.

In addition, the tracking signal generated by the recording optical head is used to ensure that the focus of the sensor objective 45 always follows the track of the sensor disk 40, and the low-pass component of the tracking signal in the low pass filter circuit in the driving circuit 53. (Not shown) is applied to the linear motor 51 to move the position of the disk in the direction in which the low frequency component of the tracking signal is reduced, in which case the track of the sensor disk 40 is continuously processed in a spiral The stage can be automatically moved from the innermost angle to the outermost angle of the sensor disk 40.

On the other hand, when the sensor objective lens 45 moves left and right by the coil for the sensor, as shown in FIG. 7, the optical axes of the objective lens 35 and the sensor objective lens 45 are shifted. As shown in FIG. 7, if the track of the sensor disk 40 is eccentric to the left by Δx, and the sensor objective lens 45 is also moved to the left to follow it, the servo laser beam is centered at a split light detector. Focusing on the left side of (60). In this case, an electric signal is generated in the laser beam position correction circuit. As the electric signal, the vibration mirror 48 is rotated by θ to move the focal point of the laser beam to the left to move the center of the light detector 60 in the form of FIG. Adjusted to focus on.

At this time, if the focal length of the optical recording objective lens 35 is f, there is a relationship of Δx = f · θ.

When this operation is made, the focus of the laser beam for the sensor follows the track of the sensor disk 40 processed precisely without eccentricity, and the focus of the recording laser beam follows the optical axis of the moved sensor objective lens 45. As a result, the recording laser beam can be exposed to the master disk 39 precisely and without eccentricity. Optical recording can be performed on the master disk 39 by turning on / off the recording laser beam moving along the precise spiral track in accordance with the signal input from the information device 54 using the optical modulator 32. have.

As described above, the information recording apparatus and method for an optical disk according to the present invention are servos which move eccentrically in accordance with information recorded in an eccentric amount measuring optical disk and a track of the optical disk for tracking servo of a recording optical disk, that is, a master disk. The recording light irradiated to the master disk by installing a vibrating mirror at the front end of the recording objective lens to correct this error by using information about the tracking error detected by the optical head and the optical system and the servo optical system. By correcting the tracks of the lower eccentricity discs under the tracks, the information recording process can be performed without the need for expensive equipment such as air bearings or ultra-precision linear stages or a work room, resulting in a low-cost device. As well as rotation of the spindle motor and translation of the linear motor (linear reciprocating) Since the movement is always sensed and controlled by the optical head, it is possible to reduce the defects caused by the wear of the precision instrument, thereby improving the productivity.

Claims (11)

Optical disc information recording comprising a recording optical head, a spindle motor and a linear motor for rotating and translating the optical disk, respectively, and driving means for driving the optical modulator of the optical head and the two motors under control of a control means. An apparatus comprising: an eccentric amount measuring optical disk for measuring an eccentricity amount caused by the translational motion of the optical disk; Tracking means for causing the recording optical head to record information along a predetermined track of the optical disk for measuring the eccentricity; And fixing means for fixing the eccentric amount measuring disk and the optical disk to be rotatable on an upper portion of the spindle motor. 2. The optical disc according to claim 1, wherein the eccentricity measuring disk is provided with a projection-shaped pit having a predetermined height in which information about a radius and a rotation angle in the disk is recorded along the tracks having a predetermined interval. Information recording device. 3. The optical disc information recording apparatus as claimed in claim 2, wherein a reflective film having a predetermined light reflectance and transmittance is formed above the pit surface. 2. The optical disc information recording apparatus according to claim 1, wherein the eccentricity measuring disk is provided to have a distance of 0.3 mm from the optical disk. 2. The tracking means according to claim 1, characterized in that the tracking means includes an optical head for measuring the eccentricity that tracks the track of the disk for measuring the eccentricity, and light reflecting means that is provided at the front end of the recording objective lens and is rotatable at a predetermined angle. Optical disk information recording apparatus. 6. The apparatus of claim 5, wherein the eccentricity measuring optical head comprises: a sensor objective lens aligned with a central axis of the recording objective lens and focused on a track of the eccentricity measuring disk; An error detection sensor optical system for providing a parallel light for detecting a focus error and a tracking error to the sensor objective lens; A dichroic mirror coinciding with the optical axis of the sensor objective lens and the sensor optical system and disposed between the sensor objective lens and the sensor optical system; And a servo optical system for detecting a tracking error from the light reflected from the dichroic mirror. The optical disc information recording apparatus according to claim 6, wherein the dichroic mirror transmits light projected from the sensor optical system and reflects servo light. The optical system of claim 6, wherein the servo optical system comprises: an optical filter which blocks light of a recording wavelength from light reflected from the dichroic mirror and passes light of an optical wavelength of the servo optical system; A focusing lens for focusing the transmitted light of the servo optical system passing through the optical filter; And optical detecting means for obtaining information on a tracking error from the transmitted light focused by the focusing lens. 9. The recording objective lens according to claim 5 or 8, wherein the rotatable light reflecting means is adapted to correct the tracking error of the recording optical head on the basis of the information on the tracking error detected from the light detecting means. An optical disk information recording apparatus characterized by changing the direction of the incident information recording light by rotation. According to claim 1, The fixing means is a disk fixing jig provided on the spindle motor; A centering jig seated on the disk fixing jig, provided with a predetermined hole at a center thereof, and configured to support and support the disk for measuring the eccentricity; A hub supporting the optical disk and seated on an upper surface of the centering jig through a through hole provided in the center of the disk for measuring the eccentricity, and having a thread formed at the center lower portion thereof; A coupling member inserted through the hole of the centering jig and coupled to the thread of the hub to tightly fix the optical disk and the disk for measuring the eccentricity; And a spacer inserted between the optical disk and the eccentricity measuring disk to maintain a predetermined distance. Irradiating the recording light emitted from the light source onto the recording optical disk through the recording objective lens; A light detection step of detecting an eccentricity off the track of the eccentricity measuring disk with the focus of the irradiated light; Calculating an eccentricity of the recording light from the detected light amount; And servoing a translational motion of the recording light incident on the recording objective lens in accordance with the calculated eccentricity information.