KR101123177B1 - Method and apparatus for forming a label - Google Patents

Abstract

In an optical disk drive configured to form a label on the label surface 14 of the recordable optical disk 10, a determination of the rotation angle α is provided so that the marking 14 on the label surface can be synchronized thereto. The method of determining the rotation angle α is one or two signals 17 which are normally present inside the optical disc drive and are generated by the Hall effect elements 17, 18, 19 used to generate the taco signal 24. ', 18', 19 '). Preferably, the actual relationship between the rotation angles a and the amplitude of these signals is recorded in the calibration procedure, allowing for a higher precision of the determined rotation angles a. This calibration procedure may be done in the process or by the user, and may not require additional special equipment if the sync pattern present on the optical disc is used to provide a reference measurement of the angle of rotation.

Optical information carrier, label formation, rotation angle, power adjustment

Description

METHOD AND APPARATUS FOR FORMING A LABEL}

The present invention relates to a method of forming a label on the label side of an optical information carrier.

The present invention also relates to an apparatus for forming a label on a label surface of an optical information carrier.

One embodiment of an apparatus for forming a label on the label side of an optical information carrier is known from US 2003 / 0161224A1, which discloses a recordable optical disc and an optical disc drive for recording to the recordable optical disc. The recordable optical disc has a label side comprising a data side and a recordable label layer, the label layer comprising a material that can be visually altered by applying thermal energy to it, for example. Thus, the optical disc drive has recording means that can be controlled to write on the label side, i.e. form the label, by applying the heat energy required to visually change the recordable label layer. The recording means may be separate from the recording means used to record the user data on the data surface, and may be located on the opposite side to the disk so that the label surface is formed at the same time as the user data is recorded. This recording means is controlled to record during the rotation of the optical disc, so that a label containing, for example, text or an image can be formed.

However, in another case, the recording mechanism may be the same as the recording mechanism used to record the user data on the data side. This means that the recording of the user data and the formation of the label must occur in two different subsequent operations. Even in this case, the recording mechanism needs to be controlled to record while rotating the optical disk.

However, recording on the label side has different results depending on whether or not user data is being recorded at the same time. In fact, while recording the user data on the data surface, the actual position recorded by the recording mechanism can be derived from the positional information existing inside the groove in which the scanning is in progress and the user data is being recorded. Alternatively, there is no groove on the label side that contains information about the actual location. In US 2003 / 0161224A1 no mention is made of how this actual position can be determined while writing on the label side as a separate action. Therefore, the conventional apparatus has the problem that a label cannot be formed when the recording mechanism used to record user data and the recording mechanism forming the label are the same, that is, more generally facing the same side of the disc. Have

Consequently, a first object of the present invention is to provide a method of forming a label on the label side of an optical information carrier, which makes it possible to form a label in a relatively broad state.

It is a second object of the present invention to provide an apparatus for forming a label on the label side of an optical information carrier, which makes it possible to form a label in a relatively broad state.

According to the invention, said first object is achieved by the method of claim 1.

The present invention is based on the idea disclosed below.

First, in order to form a label on the label surface of the optical information carrier, the actual position of the label surface, i.e., at a certain moment when the recording means is activated, is marked. Depending on the position, the recording means needs to be controlled.

Second, the position on the optical information carrier can be regarded as composed of the rotation angle and the position in the radial direction. In an apparatus for accessing an optical information carrier, hereinafter referred to as an optical disk drive, a radial position can usually be used. Similarly for an optical disk drive configured to form a label on the label surface of the optical information carrier, knowing the angle of rotation and knowing how to determine it can determine the actual position of the label surface.

Third, the parameters varying with the rotation angle are usually present in existing optical disc drives, even if they are not being used to determine the rotation angle, so that only a relatively small variation of the existing device is required, without requiring the addition of new components. The method according to the invention can be advantageously applied to such an optical disc drive.

As will be appreciated, in practice, conventional optical disc drives allow optical information carriers to coaxially interlock using a turntable motor, rotate the turntable motor, and rotate the optical information carriers together with the turntable motor. Rotates. The rotational speed of the turntable motor is usually called a tacho signal and controlled using a signal with square pulses of frequency proportional to the rotational speed. Tacosine itself does not contain information about the angle of rotation at any given moment. However, the taco signal is derived from the processing of at least one, usually three different signals, the amplitude of which differs periodically and continuously, depending on the rotation of the turntable motor and thus on the rotation angle. This other signal, hereinafter referred to as an angle dependent signal, is usually generated by a Hall effect sensor that is rotatable with respect to the magnetic field upon rotation of the turntable motor, although other configurations are possible. Usually, the magnetic field is generated by a magnet, which is the rotor of the turntable motor, while the Hall effect sensor is placed in a fixed position, i. Thus, an angle dependent signal is generated, the amplitude of which reflects the angle of rotation of the Hall effect sensor with respect to the magnet and thus the angle of rotation of the optical record carrier which is rotating with it.

Thus, the amplitude of the angle dependent signal as described above generated by the Hall effect sensor can be used as a parameter that changes continuously with the rotation angle.

The method according to the invention provides a determination of the angle of rotation, so that, for example, when the head and the recording means used for recording the user data are the same, ie more generally the same side of the optical information carrier is recorded. As is the case, the formation of the label is made possible even if the formation of the label occurs in an operation separate from the recording of the user data. However, the method according to the present invention can determine the rotation angle without involving the conversion from the address information, and thus can be advantageously applied even when the formation of the label occurs with the recording of the user data.

The method according to the invention as described above has the further advantage that it can be applied to existing optical discs, including relatively small variations of the optical disc drive itself.

In still another configuration according to the present invention, a first object is achieved by the method of claim 2. In this case, the determination of the rotation angle is used to adjust the rotation speed imposed on the information carrier by the turntable motor. This makes it possible, in particular at low speeds, to achieve an adjustment of the rotational speed which is much more accurate and reliable than the taco signal based adjustment and can be assumed to be equal to the imposed value. According to this method. Since the rotational speed can be adjusted with sufficient precision, it can be assumed that this rotational speed is equal to a known imposed value, so that adjusting the power of the recording means does not need to depend directly on the determined rotational speed, simply over time. can do. Sufficient precision in this context means precision that allows the formed labels to have good visual clarity.

In particular, the adjusted rotational speed can be a constant rotational speed, known as a constant angular velocity, as described in claim 3.

The relationship between the parameters mentioned in the method according to the invention and the angle of rotation can be derived theoretically based on the formula describing the electromagnetic phenomenon. In the case of using a Hall effect sensor to generate an angle dependent signal, this angle dependent signal may have a sinusoidal shape if graphing its amplitude versus rotational angle.

However, the inventors have found out how much the relationship between the parameters, ie the amplitude of the angle dependent signal generated by the Hall effect sensor and the rotation angle, can deviate from the theoretically derived sine wave. The actual relationship and the deviation from the resulting theoretically derived sine wave may vary from hall sensor to sensor, and even for the same hall sensor, in addition to the exact location where the hall sensor is mounted, it may vary depending on the magnet to which the hall sensor is coupled. have. As a result. In the case of using a theoretically derived relationship, systematic errors are introduced in determining the rotation angle.

To solve this problem, in a particularly preferred embodiment, the method according to the invention has the features of claim 4.

According to the invention, in the preliminary step of the method, the actual relationship between the parameter and the rotation angle is experimentally established. As a result, the determination of the rotation angle can be made more reliable and precise, thereby allowing images of better clarity and quality to be formed on the label surface. This preliminary step may be done every time a label is to be formed, but this preliminary step may only be performed once overall, since the actual relationship between the parameter and the angle of rotation depends primarily on the Hall sensor, the magnet and the connection between the two. Then, whenever the angle of rotation is determined, the experimentally established relationship is used.

To make a reference measurement of the angle of rotation, the drive needs to be connected only for preliminary steps, for example using additional hardware inside the optical disc drive, or for example an angle encoder, and special external equipment providing a reference measurement. As can be used, various methods can be considered. Preferably, reference measurements can be made using the method of claim 5.

In such a case, an optical information carrier having a synchronization pattern, for example CD, is used, where the synchronization pattern is the radial wobble modulation of the helical track. Since the wobble signal generated in wobble modulation while the track is being scanned has a frequency that depends on the nominal frequency of the wobble modulation and the scan line speed, by measuring this frequency, it is possible to measure the line speed and integrate this speed. Can be converted into angle information.

Thus, according to the present embodiment, a preliminary step can be performed without using additional hardware or external equipment connected to the drive.

Although it is possible in principle to determine the angle of rotation based on a single parameter, the use of at least one additional parameter as described in claim 6 allows for a simplified and more reliable and precise decision.

As will be apparent from the foregoing description, a second object of the present invention is achieved by an apparatus for forming a label on the label side of the optical information carrier according to claim 8 or 9. Preferred embodiments of the device according to the invention are described in claims 10, 11 and 12.

The invention and further invention of the method and apparatus according to the invention will now be described in more detail with reference to the accompanying drawings. In the accompanying drawings,

1 shows an optical disk drive modified for label formation as known in the art,

FIG. 2 shows detailed signals present in the optical disk drive shown in FIG.

3 shows a first embodiment of an apparatus for forming a label on the label side of an optical information carrier according to the present invention;

4 shows a second embodiment of an apparatus for forming a label on the label side of an optical information carrier according to the present invention.

1 shows an optical disk drive modified to form a label known in the art. An optical information carrier 10 having a label face 14 is secured with clamping means 15 to a shaft 16 extending from the turntable motor 11 and arranged approximately coaxially with the axis of rotation of the turntable motor 11. As a result, the optical information carrier 10 can be engaged by the turntable motor 11 and rotate with it. The optical information carrier 10 is arranged so that the label surface 14 faces the recording means 12 which marks the label surface 14 which is radially positionable by the radial positioning means 13. There are power adjusting means 26 for adjusting the power of the recording means 12 while rotating the optical information carrier 10.

A magnet not shown in the figure as the rotor of the turntable motor 11 generates a magnetic field that changes periodically during the rotation of the turntable motor 11.

Three Hall effect sensors 17, 18, 19 are disposed at regular positions at equal intervals along the circle around the axis of rotation, experiencing a magnetic field. Hall effect sensors 17, 18, 19 generate respective electrical signals 17 ′, 18 ′, 19 ′, and the amplitude of these signals is approximately proportional to the strength of the magnetic field experienced by each Hall effect sensor.

Since the magnetic field changes during the rotation of the turntable motor 11, the electrical signals 17 ′, 18 ′, 19 ′ output by the Hall effect sensors 17, 18, 19 also rotate the turntable motor 11. The parameters change periodically in time, so that the parameters vary continuously depending on the rotation angle α. The rotation angle α may be defined as an angle between the reference point 20 of the optical information carrier 10 and the fixed reference position 21 of the reference point 20. These angle dependent signals 17 ', 18', 19 'are signaled by the first signal processing sections 22 such that the actual value of each angle dependent signal 17', 18 ', 19' is critical. A plurality of commuting signals 17 ", 18", 19 "are obtained which are commuting between two electrical values at the moments of crossing the value. The three commuting signals 17" thus obtained are then obtained. , 18 ", 19" are combined by another signal processing unit 23 into another commuting signal known in the art as a taco signal 24, which is the three commuting signals 17 ", 18". , 19 ") has a commutation each time it has a commutation. The taco signal 24 provides pulses at a frequency proportional to the rotational speed and is used by the speed controller 25 to turntable motor Adjust the rotation speed of (11).

The apparatus further includes a head for performing read and write access. This head may be separate from the recording means 12 and may be positioned by additional radial positioning means separate from the radial positioning means 13. The head and the additional radial positioning means may be on the same side or opposite to the recording means 12 with respect to the optical information carrier 10. As an alternative thereto, the head and the recording means 12 may be positioned separately and by the same positioning means 13. Moreover, the head and the recording means 12 may be completely integral, i.e., the same apparatus is used to read or write data to the data surface and to mark the label surface 14.

Although the invention has been described with reference to an optical disk drive, ie an optical information carrier access device configured to form a label, the invention may also be particularly applicable to an apparatus for the formation of a label, the parts shown in FIG. Reference may be made.

FIG. 2 shows signals present inside the optical disk drive shown in FIG. 1, in particular three angle dependent signals 17 ′, 18 ′, 19 output by respective Hall effect sensors 17, 18, 19. '), The respective commuting signals 17 ", 18", 19 "and taco signal 24 are shown in detail.

3 shows a first embodiment of an apparatus for forming a label on the label surface 14 of the optical information carrier 10 according to the present invention. In addition to the features already shown in FIG. 1, there is an angle determiner 30 which determines the angle of rotation α of the optical information carrier 10. Two of the angle dependent signals 17 ', 18' are extracted by the measuring means 31 present in the angle determiner 30, where the actual amplitude of these signals is measured. This measurement value is given to the calculation unit 32 to calculate the rotation angle α using the relationship between the amplitudes measured for the provided measurement value and the rotation angle α. The determination of the rotation angle α can also be made with respect to the measured value of the single angle dependent signal 17 ', whereby any possible ambiguity of the rotation angle α corresponding to the angle dependent signal 17' It may be resolved by observing whether the tendency of the angle dependent signal 17 'is increasing or decreasing at the moment. However, the acquisition of two signals simplifies the decision and allows the reduction of the effects of noise. The use of all three signals 17 ', 18', 19 'is also possible. The determined rotation angle α is given to the power adjusting means, thereby adjusting the power of the recording means 12.

Since the commuting signals 17 ", 18", 19 "or taco signal 25 are not continuously varying signals but are commuting between two electrical levels, generally the actual value of any of these signals is the specific rotation angle. It would be interesting to mention that these signals cannot be used for this purpose as they cannot be associated with α and can be associated with a range of rotation angles.

Although the rotation angle α may be determined by integrating the rotation speed known in the taco signal 24 as described with reference to FIG. 1 in principle, such a determination is inevitably caused by an error that may become larger during the rotation of the disc. It would likewise be interesting to mention that it may be affected, making the determination of the rotation angle α unreliable. As the inventors recognize, this determination of the angle of rotation α may be particularly unreliable at low speeds, e. This is due to the fact that the lower the speed, the smaller the number of pulses and the larger the measurement error, since the speed is calculated as a function of the pulses counted at regular time intervals.

Alternatively, the position is derived from the value of the angle dependent parameter such as the amplitude of the signal generated by the Hall effect sensor. As an alternative to Hall effect sensors, windings may be used to capture the variation in the magnetic field.

The invention is applicable with minimal modification of the existing optical disk drive, and the measuring means 31 may be implemented as an input connected to an A / D converter inside the microcontroller, while the calculation means 32 is software. It is obvious that the whole may be implemented using functions.

The formation of the label can then occur by scanning the label surface 14 along the spiral or in concentric circles to cover the entire label surface 14 in a manner similar to when user data is recorded on the data surface. At certain moments the rotation angle is determined and the recording means is adjusted accordingly to form the desired label. If the measurement and determination of the rotation angle take too long to be performed at the required frequency, the determination of the rotation angle α may be made based on the interpolation of the most recently obtained measurement values. The selection of the reference point 20 and the reference position 21 is therefore not affecting the formation of the label.

As introduced above, the relationship between the parameter referenced in the method according to the invention and the rotation angle α may be a theoretically derived relationship. Based on the equation describing the electromagnetic phenomenon, in the above case of the amplitude of the signal generated by the Hall effect sensor, depending on how many pairs of magnetic poles are present inside the magnet, this is accomplished using one or more periods of sine wave. Can be approximated

However, such a relationship can deviate significantly from theoretically derived sine waves, so that the actual relationship is preferably established experimentally in the preliminary or calibration phase. Since the actual relationship between the parameter and the angle of rotation depends mainly on the Hall sensor, the magnet and the coupling between the two, this preliminary step can in principle be carried out once, and then every time the angle of rotation is determined, it is devoted. Use relationships built into In such cases, such calibration steps may be performed by the user prior to the first use of the device or at the factory.

Preferably, in the event of a change in the relationship due to time, use, deterioration, or environmental changes, the device should have the ability to perform a new calibration step. New calibration steps can be generated automatically or initiated by the user.

This relationship is established using the corrective means 33 as described below:

The turntable motor 11 is controlled to rotate, and at a certain moment during the rotation, the measuring means 31 and the reference measuring means 35 which provide a reference measurement value of the rotation angle α are controlled to perform simultaneous measurement. These pairs of measurements are obtained by the calibration means 33 and represent a sample of the relationship between the parameter and the rotation angle α, ie it provides a rotation angle corresponding to the given value of the parameter. This process is repeated to obtain a collection of samples with as many densities as needed, among a number of rotations. As will be apparent to those skilled in the art, various techniques are employed to filter the collection of samples to reduce the effects of noise. The collection of samples thus obtained is stored in memory in the form of a lookup table 34. During normal in-phase, the calculating means 32 retrieves the rotation angle corresponding to the obtained value of the parameter from the lookup table 34 after obtaining the value of the parameter from the measuring means 32. If the acquired value of the parameter does not exist in the lookup table, the interpolation value is calculated for the samples having the parameter values close to the obtained value. According to the experiments carried out by the inventors, it was found that in this way, it is possible to determine the rotation angle α with a precision of hundreds of degrees.

The reference measuring means 35 may be an external device which can only be used in the factory used in one calibration step. Such a device may for example be an angular encoder connectable to the shaft. Alternatively, the reference measuring means may be an internal device in which the optical disc drive is permanently provided.

In a preferred embodiment, the function of the measuring means is performed using components already present inside the optical disc drive.

In practice, optical information carriers such as CD-ROM, CD-R, CD-RW, DVD-ROM, DVD + R or DVD + RW include various synchronization patterns, from which the appropriate synchronization signals are generated during access. These synchronization signals may be used for the purpose of performing a reference measurement of the rotation angle α.

The first synchronization signal is a wobble signal. In practice, recordable optical information carriers, such as CD-R, CD-RW, DVD-R or DVD-RW, comprise spiral tracks with radial wobble modulation in which address information is encoded, which is in an ATIP / ADIP frame. It is composed of known frames and used to address sectors of user data during recording. Signals derived from wobble modulation, also known as wobble signals, having a frequency that depends on the nominal wavelength and the scan line speed, are usually used to adjust the rotational speed during recording in an optical disk drive. This signal can be used to provide speed information that is significantly more accurate than the speed information derivable from the taco signal 25, which can be processed to provide angle information.

Another sync signal is indicated by ATIP / ADIP sync. The additional synchronization signal is address information encoded in an ATIP / ADIP frame. Such address information indicates the form of positional information along the helical track, and may preferably be converted to an angle, taking into account the possible deviation of the wavelength and track pitch of the wobble from the exact numerical value specified in the standard.

Another example may be a synchronization signal present in recorded or pre-recorded user data, such as in the case of a CD, address information present in EFM sinks, subcode sinks, sectors of user data. The EFM sinks in one round can be counted and associated with the same angular spacing.

Another example of a synchronization signal is a clock period PLL reconstructed by a bit detector.

One or a combination of these synchronization signals can be used to provide a reference measurement of the rotation angle.

4 shows a second embodiment of an apparatus for forming a label on the label surface 14 of the optical information carrier 10 according to the present invention. In addition to the features already shown in FIGS. 1 and 3, there is a speed adjuster 36 that adjusts the rotation of the optical information carrier 10 at a constant angular speed. According to the present embodiment, the determined rotation angle α is given to the speed adjusting section 36 and used to adjust the rotation speed of the turntable motor 11. According to this, at low speeds, it is possible to achieve a much more precise adjustment of the rotational speed than the adjustment based on the taco signal.

In this regard, low speed means the speed at which the taco signal based adjustment does not keep the speed constant with sufficient precision, usually this is a speed of 25 Hz or less.

It is emphasized that the speed adjusting section 36 has a function different from that of the speed controlling section 25.

The speed controller 25 controls the motor based on the number of pulses counted over a relatively large time interval. The speed values that can be determined in this way are neither precise nor current. As a result, even while the high speed is sufficiently stable, a low speed which seems to be suitable during the formation of the label cannot be obtained with sufficient stability, i.e., it includes a large fluctuation of the speed. In contrast, the speed adjuster 36 controls the turntable motor 11 on the basis of precise angle determination, which is more recently determined and the rotation angle α is determined more frequently. As a result, even at a low speed, the turntable motor 11 can be controlled to precisely generate a constant angular velocity. Therefore, the power adjusting means 26 can adjust the power of the recording means 122 simply based on the time information, that is, according to the rotation angle virtually calculated by integrating the imposed constant angular velocity.

It is easy to form labels even at very low speeds, for example 1-2 Hz.

The embodiments shown in FIGS. 3 and 4 may be combined. For example, it is possible to use the rotation angle α to simultaneously obtain a low constant angular velocity and to adjust the power of the recording means. Moreover, adjusting the power of the recording means may be performed on the basis of the virtually calculated rotation angle, that is, in an open loop, in which the virtually calculated rotation angle is determined at the determined rotation angle α. Will be calibrated accordingly.

In conclusion, the user can operate as follows. Prior to the first use of the apparatus for recording on the label surface 14 of the optical information carrier 10, the data surface is directed toward the head used to access the optical information carrier, for example an optical information carrier such as CD-R. Inserted into the device, preliminary steps can be performed and relationships can be established. Thereafter, the optical information carrier 10 having the label surface 14 to be recorded is inserted with the label surface 14 facing the recording means 12, thereby making it possible to form a label. The optical information carrier used to experimentally establish the relationship in the preliminary step may be the same as or different from the optical information carrier 10 on which the label is subsequently formed. As introduced above, this evi step may be performed once before the first use as a whole or afterwards if necessary.

Although the present invention has been described with reference to an optical information carrier, it is obvious that the present invention can be applied to other applications such as rotatable non-optical information carriers. Therefore, the scope of the present invention is not limited to the above-described embodiment.

Moreover, the term "comprises / includes" when used herein, including in the claims, is used to specify the features, integers, steps or components mentioned, but one or more other features, integers Note that it does not exclude the presence or addition of elements, steps, components, or groups thereof. It is also to be noted that the word "a" or "an" preceding a component in the claims does not exclude the presence of a plurality of such components. Moreover, reference signs do not limit the claims, and the present invention may be implemented using both hardware and software, and multiple "means" may be implemented in hardware of the same item. Moreover, the present invention encompasses all novel features or combinations of these features.

The present invention can be summarized as follows. In an optical disk drive configured to form a label on a label surface of a recordable optical disk, a determination of the rotation angle may be provided so that marking of the label surface may be synchronized with it. The method of determining the rotation angle is based on one or two signals generated by Hall effect elements which are usually present inside the optical disk drive and used to generate the taco signal. Preferably, the actual relationship between the angles of rotation and the amplitude of these signals is recorded in the calibration procedure, allowing for higher precision of the determined angles of rotation. This calibration procedure may be done in the process or by the user, and may not require additional special equipment if the sync pattern present on the optical disc is used to provide a reference measurement of the angle of rotation.

Claims (12)

A method of forming a label on the label surface 14 of the optical information carrier 10 engaged by the turntable motor 11 of the optical disk drive, Rotating the optical information carrier; Based on the amplitude of the angle dependent signal that is periodically and continuously changing with the rotation of the turntable motor, by measuring a parameter that continuously changes with the rotation angle, and calculating the rotation angle using the relationship between the parameter and the rotation angle. Determining the rotation angle of the optical information carrier; Marking the label surface by rotating the optical information carrier, adjusting the power of the recording means (12) according to the determined rotation angle. A method of forming a label on the label surface 14 of the optical information carrier 10 engaged by the turntable motor 11 of the optical disk drive, Rotating the optical information carrier; Based on the amplitude of the angle dependent signal that is periodically and continuously changing with the rotation of the turntable motor, by measuring a parameter that continuously changes with the rotation angle, and calculating the rotation angle using the relationship between the parameter and the rotation angle. Determining the rotation angle of the optical information carrier; Adjusting the rotation of the optical information carrier using the determined rotation angle; Marking the label surface by adjusting the power of the recording means (12) while rotating the optical information carrier. 3. The method of claim 2, And the optical information carrier rotates at a constant angular velocity. The method according to claim 1 or 2, In the preliminary stage, Rotate the turntable motor 1, Measuring the parameters, By performing the reference measurement of the rotation angle, And establish a relationship between the parameter and the rotation angle. The method of claim 4, wherein In the preliminary step, the optical information carrier having the synchronization pattern is rotated by the turntable motor 11, and the label formation is performed by using the synchronization signal generated in the synchronization pattern to perform the reference measurement of the rotation angle. Way. The method according to claim 1 or 2, In measuring the rotation angle, based on the amplitude of the additional angle dependent signal that changes periodically and continuously with the rotation of the turntable motor, measure additional parameters that continuously change with the rotation angle, And the relationship used to calculate the rotation angle comprises an additional relationship between the parameter and the additional parameter. The method according to claim 1 or 2, In determining the rotation angle, the angle dependent signal is a signal 17 'generated by the Hall effect sensor 17 by a magnetic field that rotates with respect to the Hall effect sensor 17 in accordance with the rotation of the turntable motor 11. Label forming method characterized in that. An apparatus for forming a label on the label surface 14 of the optical information carrier 10, A turntable motor 11 for rotating the optical information carrier; Measuring means (31) for determining a rotation angle of the optical information carrier and for measuring a parameter continuously changing with the rotation angle based on an amplitude of an angle dependent signal that is periodically and continuously changing with the rotation of a turntable motor; An angle determination unit 30 having calculation means 32 for calculating the rotation angle using the relationship between the parameter and the rotation angle, Recording means 12 for marking the label surface; And a power adjusting means (26) configured to adjust the power of the recording means while rotating the optical information carrier, and adjust the power of the recording means according to the determined rotation angle. An apparatus for forming a label on the label surface 14 of the optical information carrier 10, A turntable motor 11 for rotating the optical information carrier; Measuring means (31) for determining a rotation angle of the optical information carrier and for measuring a parameter continuously changing with the rotation angle based on an amplitude of an angle dependent signal that is periodically and continuously changing with the rotation of a turntable motor; An angle determination unit 30 having calculation means 32 for calculating the rotation angle using the relationship between the parameter and the rotation angle, A speed adjusting unit 36 for adjusting the rotation of the optical information carrier using the determined rotation angle; Recording means 12 for marking the label surface; And a power adjusting means (26) for adjusting the power of the recording means while rotating the optical information carrier. The method of claim 9, The speed adjusting unit (36) is a label forming apparatus, characterized in that configured to adjust the rotation of the optical information carrier (10) at a constant angular speed. The method according to claim 8 or 9, Further comprising calibration means 33 for establishing a relationship between the parameter and the rotation angle, wherein the calibration means, To control the turntable motor 11 to rotate, The measuring means 31 is controlled to measure the parameter to obtain the measured parameter, And a reference measuring means (35) to perform the reference measurement of the rotation angle, so as to obtain a reference measurement value. The method according to claim 8 or 9, Further comprising a Hall effect sensor 17 for generating said angle dependent signal 17 ', The angle forming signal (17 ') is generated by a magnetic field rotating with respect to the Hall effect sensor (17) as the turntable motor (11) rotates.

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