JP2006209868A - Disk and method for inspecting optical pickup device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To inspect various characteristics of an optical pickup device corresponding to a plurality of kinds of optical disks equal in used wavelengths and in thickness of transparent substrates on a signal recording surface by one optical disk in an optical pickup device inspecting disk for inspecting the characteristics of an optical pickup device. <P>SOLUTION: In the optical disk having a reflection film not changed in reflectance characteristics even when it is irradiated with a reproducing or recording laser beam, the disk is divided into inner and outer peripheral sides to form groove and pit areas 2 and 1, the depths of the groove in the groove area 2 and the pit of the pit area 1 are set to 1/6 to 1/5 of a used wavelength, and the groove is formed to meander at a predetermined cycle to detect a wobbling signal. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical pickup device inspection disk and an optical pickup device inspection method for inspecting characteristics of an optical pickup device that records or reproduces an information signal by irradiating a laser beam onto an optical recording medium.

  2. Description of the Related Art Conventionally, an optical disk that records or reproduces an information signal by irradiating a laser beam has attracted attention as a person who plays a central role in a recording medium in a highly information society. Examples of such an optical disc include “CD” (Compact Disc: trade name) on which music information and computer programs are recorded, and “DVD” (Digital Versatile Disc: trade name) on which image information is recorded. Are known.

  In these optical discs, the wavelength used is the same and the transparent substrates on the signal recording surface have the same thickness, and the information signal can only be reproduced (ROM disc). Proposals have been made of those that can be recorded (added) only once (R / RW disc), those that can erase and record (overwrite) information signals (RAM disc), and the like.

  In such an optical pickup device that performs recording or reproduction using various optical disks, specifications of signals to be reproduced or recorded are determined for each type of optical disk. Therefore, in the manufacturing process of such an optical pickup device, in order to inspect the characteristics of this optical pickup device, the signal is reproduced or recorded using each type of optical disc, the state of each signal is measured, It is necessary to judge.

  Therefore, in order to inspect the characteristics of such an optical pickup device, as shown in FIG. 13, an inspection device 104 corresponding to recording / reproduction of a plurality of types of optical disks 101, 102, 103 is prepared. The optical pickup device 105 to be inspected is mounted, the disk is exchanged a plurality of times, and an inspection process corresponding to each optical disk is performed. The inspection device 104 needs to be compatible with a plurality of types of optical disks 101, 102, and 103 that are compatible with the optical pickup device to be inspected.

Patent Document 1 discloses an inspection disk for inspecting and adjusting the characteristics of an optical pickup device that reproduces “CD” and “DVD” like an optical pickup device for a “DVD” optical pickup device. As shown in FIG. 4, there is described a composite disc in which “CD” and “DVD” are divided into areas on the inner and outer circumferences of one optical disc. This inspection disk is configured to have an area 101a having a disk thickness of 0.6 mm and an area 101b having a disk thickness of 1.2 mm. In one inspection apparatus, the disk can be replaced without replacing the disk. It is possible to inspect and adjust the characteristics of the optical pickup device for reproducing “CD” and “DVD”.
JP 2001-291274 A

  By the way, in the inspection of the characteristics of the conventional optical pickup device, as described above, in each inspection process, an optical disk required in that process must be mounted on the inspection apparatus, so that the disk is replaced for each inspection process. It will be. Therefore, in the inspection of the characteristics of such an optical pickup device, duplicate operations occur in each inspection process, and the inspection time cannot be shortened.

  Further, in the inspection of the characteristics of such an optical pickup device, since each inspection process is performed using different optical disks after disk replacement, it is difficult to maintain the compatibility of the inspection results in each inspection process. is there.

  Since the composite disk as described above must be able to be constructed by a single cutting process, the characteristics of the optical pickup device for reproducing “CD” and “DVD” are inspected and adjusted for adjustment. For example, it is impossible to construct a composite disk including a plurality of disk formats in “DVD”. A plurality of disc formats in “DVD” use the same wavelength and disc thickness, but include playback and recording, and have different groove structures, groove depths, and the like.

  Furthermore, as an optical disk for inspecting the characteristics of the optical pickup device for recording, an optical disc having a signal recording layer on which signals are recorded by the optical pickup device is used. In the step of inspecting the push-pull balance at the time of recording using this optical disc, the emitted light from the optical pickup device is used as the recording optical power without performing the tracking control. For this reason, recording is also performed on portions other than the groove on the optical disk, and an abnormal state that cannot be normally recorded is recorded. In this optical disc, the characteristics differ depending on the number of times of overwriting. Therefore, the area once used cannot be used in the inspection of the next optical pickup device, and the inspection of the next optical pickup device It is necessary to use it. Accordingly, each time the optical pickup device is inspected, the recorded area increases, and when there is no unrecorded area, the optical disk cannot be used. Therefore, management of the area on the optical disk is troublesome.

  Accordingly, the present invention has been proposed in view of the above circumstances, and an optical pickup for inspecting the characteristics of an optical pickup device that records or reproduces an information signal by irradiating a laser beam onto an optical disk. In the apparatus inspection disk and the optical pickup apparatus inspection method, various characteristics of the optical pickup apparatus corresponding to a plurality of types of optical disks having the same operating wavelength and the same thickness of the transparent substrate on the signal recording surface are described. It is an object to allow inspection to be performed with a single optical disk.

  In order to solve the above-described problems, in the present invention, the parameters of the optical pickup device inspection disk are signal characteristics that can be correlated with the signal characteristics obtained when a plurality of types of separate optical disks are used, In addition, by using a ROM disk that does not perform recording even when the light emitted from the optical pickup device is used as the recording power, it is possible to perform inspections for reproduction and recording by a single inspection without replacing the disk. Is. Then, a correlation with signal characteristics read from a plurality of types of separate optical disks corresponding to the optical pickup device is grasped in advance, and the characteristics of the optical pickup device are inspected based on the correlation.

  That is, the optical pickup device inspection disk according to the present invention has the following configuration.

[Configuration 1]
Used for inspecting the characteristics of an optical pickup device corresponding to a plurality of types of optical discs having the same wavelength and having the same transparent substrate thickness on the signal recording surface at one time. An optical pickup device inspection disk for inspecting characteristics of an optical pickup device that records or reproduces an information signal by irradiating a beam, which is irradiated with either a reproduction laser beam or a recording laser beam It has a reflective film whose reflectance characteristics do not change, and a groove area and a pit area formed by being divided into an inner peripheral side and an outer peripheral side, and the depth of the pits in the groove and pit areas in the groove area is used. 1/6 to 1/5 of the wavelength, and the groove meanders at a predetermined period in order to detect a wobble signal. It is.

  This optical pickup device inspection disk has a reflective film whose reflectance characteristics do not change when irradiated with either a reproduction laser beam or a recording laser beam. The characteristics do not change even when the emitted light is irradiated, and the inspection process performed using the recording disk can be repeated many times.

  This optical pickup device inspection disk has a pit area characteristic equivalent to that of a normal ROM disk. Further, as a push-pull-related signal characteristic to be evaluated with a recording disk, the original recording disk ([ -R] disk or [-RW] disk) is obtained, and the characteristics of the optical pickup device can be estimated from the correlation coefficient grasped in advance. In addition, this optical pickup device inspection disk can also be subjected to wobble inspection.

  And the optical pick-up apparatus test | inspection method based on this invention has the following structures.

[Configuration 2]
A laser beam is applied to the optical disc in order to inspect the characteristics of the optical pickup device corresponding to a plurality of types of optical discs that use the same wavelength and have the same transparent substrate thickness on the signal recording surface. In an optical pickup device inspection method for inspecting characteristics of an optical pickup device by irradiating and recording or reproducing an information signal, a signal read from an optical disk corresponding to the optical pickup device by the optical pickup device and the optical pickup device The correlation with the signal read from the optical pickup device inspection disk described in 1 is set in advance, and the characteristics of the optical pickup device are inspected from the read signal and the correlation using the optical pickup device inspection disk. It is characterized by doing.

  In this optical pickup device inspection method, since an optical pickup device inspection disk is an optical disk having a reflective film whose reflectance characteristics do not change when irradiated with either a reproduction laser beam or a recording laser beam, Even when the light emitted from the optical pickup device with recording power is irradiated, the characteristics of the optical pickup device inspection disk do not change, and the inspection process performed using the recording disk can be repeated many times.

  The optical pickup device inspection disk used in this optical pickup device inspection method has a pit area characteristic equivalent to that of a normal ROM disk, and as a push-pull-related signal characteristic to be evaluated with a recording disk. A signal characteristic equivalent to that obtained when an original recording disk ([-R] disk or [-RW] disk) is used is obtained, and the characteristic of the optical pickup device is estimated from a correlation coefficient grasped in advance. Can do. Further, in this optical pickup apparatus inspection method, a wobble inspection is also possible.

  In the optical pickup device inspection disk and the optical pickup device inspection method according to the present invention, recording or reproduction is performed on a plurality of types of optical disks having the same wavelength used and the same transparent substrate thickness on the signal recording surface. The inspection of the characteristics of the optical pickup device performing the above can be quickly performed at once using one optical pickup device inspection disk.

  This optical pickup device inspection disk is an optical disk having a reflective film whose reflectance characteristics do not change when irradiated with either a reproduction laser beam or a recording laser beam. The characteristics do not change even when the light emitted from the recording medium is irradiated, and the inspection process performed using the recording disk can be repeated many times.

  This optical pickup device inspection disk has a pit area characteristic equivalent to that of a normal ROM disk. Further, as a push-pull-related signal characteristic to be evaluated with a recording disk, the original recording disk ([ -R] disk or [-RW] disk) is obtained, and the characteristics of the optical pickup device can be estimated from the correlation coefficient grasped in advance. In addition, this optical pickup device inspection disk can also be subjected to wobble inspection.

  That is, the present invention relates to an optical pickup device inspection disk and an optical pickup device inspection method for inspecting characteristics of an optical pickup device that records or reproduces an information signal by irradiating a laser beam to the optical disk. The optical pickup device corresponding to a plurality of types of optical discs having the same thickness and the same thickness of the transparent substrate on the signal recording surface can be inspected with a single optical disc. To do.

  Hereinafter, the best embodiment of the optical recording medium of the present invention will be described with reference to the drawings.

[Configuration of Optical Pickup Device Inspection Disk According to the Present Invention]
The optical pickup apparatus whose characteristics are inspected in the present invention is compatible with a plurality of types of optical disks having the same wavelength used and the same transparent substrate thickness on the signal recording surface. The plural types of disks are, for example, a ROM disk (playback-only disk), an R / RW disk (recording disk), and a RAM disk (overwrite recording disk). In these optical discs with different formats, the embossed part of the control signal area must have signal characteristics that can be read by the optical pickup device. There are differences depending on the structure, groove structure, reflection film characteristics, and the difference in the reproduction principle of the RF signal.

  FIG. 1 is a plan view and main part perspective view showing the configuration of an optical pickup device inspection disk according to the present invention.

  As shown in FIG. 1, the disk used for the inspection of the optical pickup device according to the present invention has a pit area (ROM disk area) 1 formed on the inner peripheral side and a groove area on the outer peripheral side, as shown in FIG. 2 and a reflection film for a ROM disk. The depths of the pits and grooves are preferably 20 nm to 30 nm corresponding to the grooves of the R / RW disc, or λ / 5 to λ / 6 that can obtain a PP signal equivalent to this.

  In addition, for R / RW discs of “DVD”, in order to support copy management, the control data part can be controlled by selecting the glass material, controlling the exposure amount to a resist thickness according to the etching method, embossing, etc. By forming regions with different cutting parameters (embossed portion and groove depth), the pit region and the groove region are combined and combined.

  The optical pickup device inspection disk according to the present invention is also configured to have the pit area 1 and the groove area 2 on the same disk by dividing the radial position by such a method.

[Outline of Optical Pickup Device Inspection Method According to the Present Invention]
In an optical pickup apparatus that records or reproduces an information signal by irradiating a laser beam to an optical disk, the following characteristics are not related to the type of optical disk to be used.

(1) Characteristics of the forward optical system for forming a light spot for reading and writing signals (2) Characteristics of the backward optical system for transmitting reflected light from the optical disk to the light receiving element (3) Electricity of reflected light by the light receiving element Characteristics of the light receiving system converted into signals These characteristics can be inspected using an optical measuring system. If the degree of influence of these characteristics on the signal characteristics required for various disk formats is known in advance, the characteristics of the optical pickup device can be determined based on the inspection results using an optical measurement system. Can be managed.

  In the optical pickup apparatus inspection method according to the present invention, inspection items that require the use of an inspection disk are also inspected using a single optical disk having parameters common to a plurality of disk formats. By knowing in advance the correlation with the signal characteristics obtained when using separate optical discs corresponding to, the test results for each test item can be estimated from the test results using a single optical disc. To do.

[About multiple types of optical discs supported by optical pickup devices]
FIG. 2 is a perspective view showing the structure of each type of optical disc in “DVD”.

  In “DVD”, the ROM disk (reproduction-only disk) shown in (a) of FIG. 2, the R / RW disk (recording disk) shown in (b) of FIG. 2, and (c) of FIG. There is a RAM disk (overwrite recording disk) shown. In “DVDs” having different formats, the embossed portion of the control signal area is required to have signal characteristics that can be read by the optical pickup device. There are differences depending on differences in the pit structure, groove structure, reflection film characteristics, RF signal reproduction principle, and the like.

  By the way, the RF signal level is detected by intensity modulation of the total reflected light and has a modulation degree specification (60% or more) that can be read by the optical pickup device. Judgment can be made.

  As for jitter, the recording characteristics of the ROM disk, the R / RW disk, and the RAM disk can be determined based on the above-mentioned optical common items.

  Further, regarding the focus error signal level signal for focus control, the difference between the ROM disk, the R / RW disk, and the RAM disk is the difference in reflectance, and can be determined by inspection using the ROM disk.

  Further, the focus shift characteristic due to the position shift of the photodetector (PD) can be determined by inspection using a ROM disk. In addition, since the characteristic change due to defocusing is related to the spot characteristic, it can be determined by the optical common items described above.

  The tracking signal needs to be inspected using an inspection disk because the signal characteristics differ depending on the disk structure.

  That is, in the optical pickup device to be inspected here, a DPD (Differential Phase Detection) signal is detected as a tracking signal in the ROM disk. The R / RW disc has a structure having a groove and LPP (Land Pre-Pit). In an optical pickup device, a DPP (Differential Push-Pull) signal in which a push-pull signal is stabilized is used as a tracking signal. Is used. In the RAM disk, a land groove system is adopted, and in the optical pickup device, a push-pull signal is used alone as a tracking signal, and a characteristic with good control performance is obtained.

  As described above, the tracking signals have different signal characteristics depending on the disc structure, and the inspection is performed using the inspection disc.

  The specification of the DPD signal that is a tracking signal must be able to be reproduced for all “DVDs” in terms of reproduction characteristics, and has a strong correlation with inspection characteristics when reproducing a ROM disk. It can be determined by inspection using

  Further, in a recording disk (R / RW disk and RAM disk), an address signal and a wobble signal are detected by a push-pull method. Therefore, it is necessary to inspect the quality of push-pull signals that are not used in the ROM disk (normal reproduction and lens shift, tolerance during defocus, and fluctuation during recording).

  Since the push-pull signal is the same principle as the recording disk with respect to the depth of the groove, the basic detection method is the same principle if a testing disk having parameters that are considered to be the same with a symmetrical value in terms of signal characteristics is used. A certain relationship is recognized between these recording disks and inspection disks, and there is a strong correlation. In the present invention, using such correlation, the signal characteristics obtained by one inspection using one type of inspection disk are changed to signal characteristics obtained when another recording disk or the like is used. This makes it possible to determine the characteristics of the optical pickup device without using a plurality of types of optical disks, and to simplify the inspection process.

  FIG. 3 is a graph showing the change of the far field pattern when the relative position of the groove and the spot changes.

  As shown in FIG. 3, a tracking signal appears when the light spot on the optical disk crosses the groove. A wobble signal appears because the groove has a periodic beat (meander) at a very small level.

  FIG. 4 is a graph showing the change of the far field pattern and the LPP detected by the differential operation and the wobble waveform when the spot scans the LPP (Land Pre-Pit) where the land is interrupted.

  For example, the wobble period is 140.645 KHz, and the amplitude of the wobble to be wobbled is normalized by the push-pull signal level, and 0.08 <[wobble amplitude / MPP amplitude] <0.14. In the RAM disk, the address (CAPA) signal and the land and groove tracking signals are detected by differential calculation.

  Here, the level of the PP (Push-Pull) signal when the groove type disc (R / RW disc and RAM disc) and the pit type disc (ROM disc) are reproduced has the following relationship.

PP = r · sin (πw / p) · sin (4πd / λ) · sin (2πu / p)
(W is the width of the groove (groove), p is the pitch, d is the depth of the groove, and u is the misalignment between the reading spot and the groove.)
FIG. 5 is a graph showing the relationship between the groove depth (d) and the PP signal level in the relational expression.

  As shown in FIG. 5, the push-pull signal, which is the difference between the right and left in the intensity distribution of the reflected light from the optical disk, becomes the maximum when the wavelength of the laser beam is λ and the groove depth is λ / 8. It has a characteristic that the level is lowered symmetrically before and after.

  In the R / RW disc, the address signal is formed by land pre-pits (LPP), a good jitter characteristic is obtained by groove recording, and a push-pull tracking signal and LPP signal (LPP signal to RF signal) are obtained. The groove depth is 20 nm to 30 nm in order to improve the reproduction characteristics (including a range with a low degree of interference).

  On the other hand, in the ROM disk, the structural dimension parameter is defined by the fact that the modulation degree of the RF signal is 0.6 or more, and the characteristics of the DPD signal and TPP (Tangential Push-Pull) signal, and the pit depth is , Λ / 4 (110 nm).

  The RAM disk has a structure in which lands and grooves are mixed, and the groove depth has a specification of λ / 6 (74 nm).

[Displacement of photodetector (PD) in optical pickup device]
Next, the shift of the dividing line of the light receiving pattern in the photodetector (PD) of the optical pickup device will be described.

  FIG. 3 described above shows a case where the spot crosses the groove and the photodetector (PD) of the optical pickup device is accurately divided at the center of the light receiving pattern. Here, the light receiving optical system receives the light. If it deviates from the center of the pattern, the PP signal balance is lost. FIG. 3 is an explanatory diagram of the PP signal, and shows a far field pattern when the result of the differential operation is maximized.

  FIG. 6 is a front view showing a far field pattern when the relative positions of the groove and the spot in the R / RW disc and the RAM disc are changed.

  FIG. 7 is a front view showing a state of deviation of the light receiving pattern dividing line of the photodetector (PD) of the optical pickup device.

  FIG. 8 shows a PP signal on the R / RW disc ((a) in FIG. 8) and a PP signal on the RAM disc (FIG. 8) when the light receiving pattern dividing lines of the photodetector (PD) of the optical pickup device are shifted to the same extent. 8 is a graph showing (b) in FIG.

  In the R / RW disc, since the groove is shallow, as shown in FIGS. 6 to 8, the modulation degree of the PP signal is small, and the push-pull signal of the light receiving pattern dividing line of the photodetector (PD) and the light intensity balance are reduced. Fluctuation is large. Such misalignment of the dividing lines affects the viewpoint of stable operation of the servo and the detection accuracy of the LPP signal and the wobble signal.

  By the way, the tracking signal is detected using three laser beams by the DPP method. That is, PP signals are formed by the main beam and the two sub beams, respectively, and the tracking signals are out of phase with each other, and the offset due to stray light and lens shift is canceled out in phase, thereby stabilizing the operation. Yes. Here, it is important that the PP signal is balanced and fluctuates in phase between the main beam and the sub beam.

  If the detection sensitivity difference of the light receiving element of the photodetector (PD) in the light receiving system and the mixing of stray light are unbalanced, a difference will occur in the in-phase fluctuation of the PP signal. Since the PP signal balance is controlled by the position adjustment accuracy of the light receiving element that divides the reflected light beam, it is preceded by the accuracy control of the dividing line of the light receiving element. However, it is necessary to inspect even the actual signal. In order to evaluate whether the reflected light from the optical disk is divided at the center of the far field distribution, it is necessary to inspect the balance of the photodetector (PD).

  However, the divergence angle of the far field pattern of the semiconductor laser, which is a light emitting element, varies between the time when the reproducing power is emitted and the time when the recording power is emitted in a recent real refractive semiconductor laser. In addition, in a semiconductor laser employing a window structure to improve electrostatic characteristics, the refractive index of the window structure medium on the light emitting surface is different from that of the laser chip. Tend to tilt. Therefore, there is a problem that the pattern is moved by the light emission power and the same phenomenon occurs when the dividing line is changed, and the balance of the photodetector (PD) is lost. Furthermore, cross current between the light receiving elements of the photodetector (PD) may cause photocurrent to enter other light receiving elements and disturb the effective division position. These are equivalent to the variation of the dividing line when the far field pattern is differentially detected, and affect the variation characteristics of the PP signal, and therefore must be managed in the inspection process.

  FIG. 9 is a waveform diagram showing the definition of the balance of the PP signal (tracking signal).

  As shown in FIG. 9, the balance of the PP signal (tracking signal) is expressed by dividing the amount of deviation of the midpoint of the signal from the ground (GND) by the signal amplitude (that is, the + side amplitude is A and the − side amplitude is). Is B, the balance of the tracking signal is represented by {(A−B) / 2 (A + B)} × 100 (%)). In an optical pickup device that records a signal, it is necessary to inspect the balance of the PP signal for both the reproduction operation and the recording operation. This is because even if the power of the emitted light is increased, it can be assumed that the proportional relationship is maintained with respect to the balance of the PP signal, but the proportional relationship is not achieved due to various factors.

  Even if the tracking signal is stabilized by the DPP method, the fact that the balance is shifted is a state in which the position of the dividing line in the photodetector (PD) is not optimal. In this state, when a track that has already been recorded is reproduced and an LPP signal or wobble signal is detected, the recorded RF signal component is not canceled and a high-quality signal cannot be obtained.

  FIG. 10 is a waveform diagram showing a state in which the recording signal indicating the signal of the recording unit is mixed in the LPP signal and the wobble signal.

  At the time of recording operation, as shown in FIG. 10, the emitted light power becomes a recording light level, which is about 10 times that during reproduction. Even in this state, the tracking signal needs to be balanced.

  Further, the wobble signal and the LPP signal are premised on that the fluctuation component of the optical power change that changes in a pulse shape by the strategy for recording is canceled by the differential during the recording operation. The intensity balance of each element for performing the differential needs to be several percent or less. Therefore, it is necessary to inspect the balance of the PP signal in order to stabilize the detection characteristics during recording. As described above, the PP signal balance needs to be confirmed both during the reproduction operation and during the recording operation.

  A ROM disk equivalent to the push-pull signal output with respect to the R / RW disk is obtained from the above-described relational expression. That is, the groove depth of 25 nm corresponds to λ / 17 when the refractive index of the disk substrate is 1.55 and the reproduction wavelength is 660 nm. The groove depth at which the same tracking signal can be obtained is a symmetric depth centered on λ / 8. Therefore, from [λ / 8− (λ / 8−λ / 17)], [13 (λ /68)=λ/5.2=81.4 nm (n = 1.55)].

  Also, since the groove width is the maximum at half the pitch, it is proportional regardless of whether it is close to that of the ROM disk. If the correlation is verified on the disk used for the inspection, a compatible relationship can be obtained. I can take it off.

  The RAM disk adopts a land groove system, and the groove depth is about 70 nm. The tracking signal, address signal (CAPA), and wobble signal detected by the push-pull system have higher quality than the parameters of the R / RW disk. good. Therefore, it may be inspected with a strict R / RW disc.

  In the case of a RAM disk, the RF signal quality of the control track section is allowed to a level where the range of the modulation degree is low according to the standard, and is inferior in principle. Therefore, it is necessary to estimate the characteristics of this signal.

[Optical Pickup Device Inspection Method According to the Present Invention]
FIG. 11 is a graph showing the correlation between the MPP balance in the pit area and the groove area in the optical pickup device inspection disk according to the present invention.

  In the optical pickup device inspection disc according to the present invention, the MPP balance in the pit area and the groove area has a strong correlation as shown in FIG. 11, and it can be judged that evaluation using the pit area is sufficient. That is, signal characteristics in the R / RW disc and the RAM disc can be estimated by reproducing a pit region having a pit depth of λ / 5 to λ / 6 and measuring the balance of the PP signal.

  The fluctuation of the balance of the PP signal during the recording operation is such that if the optical power is equivalent to the recording level (reflectance of each disk × recording power), the reflected light amount becomes the recording state, and the PP signal balance at this time is inspected. Can be judged. The light intensity of the two light receiving elements forming the PP signal is obtained by an average waveform value, and an index indicating the balance of the light intensity between the sum signal and the differential component is obtained, thereby detecting the LPP signal and the wobble signal during the recording operation. It is also possible to estimate the amount of wraparound of the strategy waveform when

  As shown in FIG. 10, when the playback operation is switched to the recording operation in the R / RW disc, the tracking signal, the wobble signal, and the LPP signal change in waveform when the operation is switched. The same characteristics as this can be evaluated by changing the optical power corresponding to the recording power even when this inspection disk is used. In addition, the tracking signal is inspected with the tracking servo operation turned off, but since this inspection disk has a reflective film for ROM disk, the signal is not recorded by one recording disk, The inspection can be repeated any number of times.

  In the pit area, only the tracking signal can be evaluated, but the balance state when detecting the LPP signal and the wobble signal can be inspected based on the balance of the push-pull signal. In the groove area having the groove structure of the R / RW disc, the LPP signal and the wobble signal during the recording operation can be evaluated.

  In this way, in this optical pickup apparatus inspection method, it is possible to estimate the characteristics of the PP signal when the reproduction operation and the recording operation are performed using each type of separate optical disc. By such an inspection, it is possible to inspect an optical pickup device compatible with a plurality of types of optical disks with a small number of inspection steps.

  FIG. 12 is a side view showing an inspection apparatus for executing the optical pickup apparatus inspection method according to the present invention.

  That is, in the optical pickup device inspection method according to the present invention, as shown in FIG. 12, the inspection relating to various characteristics of the optical pickup device 5 is performed with one inspection disk 3 mounted on the inspection device 4. It can be performed.

FIG. 2 is a plan view and a main part perspective view showing a configuration of an optical pickup device inspection disk according to the present invention. FIG. 3 is a perspective view showing the structure of each type of optical disc in an optical disc (“DVD”). It is a graph which shows the change of a far field pattern when the relative position of a groove and a spot in an optical disk changes. It is a graph which shows the change of a far field pattern when a spot scans LPP (Land Pre-Pit) which is the interruption of the land in an optical disc, and the LPP detected by the differential calculation, and a wobble waveform. It is a graph which shows the relationship between the depth of the groove | channel (groove | groove) in an optical disk, and the level of PP (push pull) signal. It is a front view which shows a far field pattern when the relative position of the groove | channel and a spot in a R / RW disc and a RAM disc changes. It is a front view which shows the state of the shift | offset | difference of the light-receiving pattern division line of the photodetector (PD) of an optical pick-up apparatus. It is a graph which shows PP signal in the R / RW disc and PP signal in the RAM disc when the light receiving pattern dividing lines of the photodetector (PD) of the optical pickup device are shifted by the same degree. It is a wave form diagram which shows the definition of the balance of PP signal (tracking signal). It is a wave form diagram which shows the state in which the recording signal which shows the signal of a recording part is mixed in the LPP signal and the wobble signal. 4 is a graph showing a correlation between MPP balances in a pit area and a groove area in an optical pickup device inspection disc according to the present invention. It is a side view which shows the test | inspection apparatus which performs the optical pick-up apparatus test | inspection method which concerns on this invention. It is a side view which shows the conventional test | inspection apparatus which test | inspects an optical pick-up apparatus. It is a top view which shows the structure of the conventional composite disk.

Explanation of symbols

1 Pit area 2 Groove area

Claims (2)

Used for inspecting the characteristics of an optical pickup device corresponding to a plurality of types of optical discs having the same wavelength and having the same transparent substrate thickness on the signal recording surface at one time. An optical pickup device inspection disk for inspecting characteristics of an optical pickup device that records or reproduces an information signal by irradiating a laser beam,
A reflective film whose reflectance characteristics do not change when irradiated with either a reproduction laser beam or a recording laser beam;
It has a groove area and a pit area formed by being divided into an inner peripheral side and an outer peripheral side,
The depth of the groove in the groove region and the pit in the pit region is 1/6 to 1/5 of the wavelength used,
The optical pickup device inspection disk, wherein the groove meanders at a predetermined period to detect a wobble signal. In order to inspect the characteristics of the optical pickup device corresponding to a plurality of types of optical discs having the same wavelength used and the same thickness of the transparent substrate on the signal recording surface, a laser is applied to the optical disc. In an optical pickup device inspection method for irradiating a beam to record or reproduce an information signal and inspect the characteristics of the optical pickup device,
A correlation between a signal read from the optical disc corresponding to the optical pickup device by the optical pickup device and a signal read from the optical pickup device inspection disc according to claim 1 by the optical pickup device is set in advance,
An optical pickup device inspection method, wherein the optical pickup device inspection disk is used to inspect characteristics of the optical pickup device from a read signal and the correlation.

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