JP2002367187A - Device and method for adjusting inclination angle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device and a method for adjusting the inclination angle of a pickup module with which device for realizing at least the focus ON by adjusting the recording face of an optical disk and a plane formed by two shafts on which the pickup is mounted to be parallel to each other as a preliminary procedure of the adjustment of the inclination angle. SOLUTION: The device is composed of: a recording medium 8 mounted on a recording medium mounting part 1; an inclination angle signal detection part 100 which detects the inclination angle of the recording medium 8 with respect to a reference plane; an inclination angle adjustment part 110 which adjusts the inclination angle of the pickup 2 by vertically changing the height of shafts 6 by turning a position adjustment member 7 with a turnable bit 9; a height difference measuring part 120 which turns and measures the difference in height of the shafts 6 with a contact type displacement sensor; an adjustment amount setting part for inclination angle 130 which derives the inclination Θ in the radial direction and the inclination Φ in the tangential direction of the shafts with respect to the reference plane and stores the inclinations in an internal memory; and a jitter value measuring part 140 which measures a jitter value from the reproduced signal of the information recorded in the recording medium 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for adjusting the tilt angle of a pickup module in a manufacturing process of an optical disk information recording apparatus.

[0002]

2. Description of the Related Art A pickup in an optical disk drive uses an actuator for moving an objective lens up and down and left and right according to the polarity of a permanent magnet and the polarity of a magnetic field generated during conduction, and setting the objective lens position to a desired position. As a result, a signal for proper focus and tracking drive can be obtained. Ideally, the tilt angle of this actuator should have a constant value. However, in actuality, there is a difference in the relative positional relationship between the mounting position of the permanent magnet and the mounting position of the magnetic field generating coil during assembly. The value shifts in the range of. As a result, in the optical disk device, even if the pickup is assembled by a fixed assembling method, the positional relationship between the recording medium and the pickup may deviate from the original positional relationship. For this reason, an optical signal error occurs due to an optical axis shift or the like, and as a result, problems such as a difficulty in moving the pickup and a failure in obtaining a sufficient reproduction signal as data occur. Therefore, a tilt adjustment step is generally provided to relatively change the tilt of the optical disk and the tilt of the objective lens so as to adjust the positional relationship so as to minimize the error of the optical signal.

Japanese Patent Application Laid-Open No. 9-320214 discloses an optical disk apparatus in which the relative angle between an optical disk and a pickup head is kept within an allowable inclination to improve accuracy by rational adjustment and a guide shaft adjusting method. It has been disclosed.
Referring to FIG. 20, first and second parallel guide shafts 12a and 12b for supporting the pickup head 11 in the radial direction of the optical disk 10 are provided at least in the first guide shaft 12a.
The first adjusting member 15a and the second adjusting member 15b, which support both ends of the guide shaft of which the height can be adjusted, and the one end of the second guide shaft which supports the height and can adjust the height. A line segment a1-a2 connecting the guide shaft support points of the first and second adjustment members, and a line segment b1 connecting the guide shaft support points of the second and third adjustment members. −b2 was set so as to be orthogonal, and the extension line c1-c2 of the movement trajectory of the pickup head was set to coincide with the rotation center O of the optical disk. Thereby, the relative angle between the optical disk and the pickup head is kept within the allowable inclination, and improvement in accuracy can be measured by rational adjustment.

Japanese Patent Laid-Open No. 2000-57607 discloses an optical pickup, an inclination adjusting means for adjusting the inclination of the optical pickup, and a jitter detecting means for detecting a jitter amount of a reproduction signal generated from the optical pickup. There has been proposed an optical recording / reproducing apparatus including an inclination control unit that feeds back the amount of jitter detected from the jitter detection unit to the inclination adjustment unit and controls the amount of jitter to be minimized. It is said that there is no need to provide a displacement sensor for detecting the inclination in opposition to the recording medium, and there is an advantage that there is no restriction on the installation space.

[0005]

However, in the tilt adjusting step as described above, the tilt of the optical disk and the tilt of the objective lens are relatively changed to adjust the positional relationship so as to minimize the error of the optical signal. are doing. In any of the configurations of the related art, it is premised that the focus and track signals are obtained at the start of the tilt angle adjustment and the jitter value is obtained. However, the tilt angle between the optical disc and the objective lens before the tilt angle adjustment is large, and the focus is not turned on at the start of the tilt angle adjustment, so that a jitter value cannot be obtained, and the tilt angle adjustment cannot be started. Further, since it is not possible to isolate a defect for each component such as a pickup / media mounting unit, even if an attempt is made to readjust, only the same focus NG is repeated.
There was the inconvenience of having to separately analyze component defects. The present invention has been made in view of the above-mentioned problems, and as a process before the tilt adjustment, a recording surface of an optical disc and a plane formed by two shafts on which a pickup is mounted are set to be parallel. An object of the present invention is to provide a tilt adjusting device and a tilt adjusting method of a pickup module that can at least focus ON by adjusting.

[0006]

In order to solve the above-mentioned problem, the present invention calculates a tilt adjustment amount according to a jitter value measured from a reproduced signal, and calculates a tilt angle based on the tilt adjustment amount. In a tilt adjustment device for a pickup module of an optical disc information recording device for performing adjustment, a jitter value measuring means for measuring a jitter value based on a reproduction signal from an optical disc recording medium; Height difference measuring means for measuring a height difference between one or more other different points on a shaft having the reference point and a plurality of points on a shaft not having the reference point and the reference point Tilt signal detection means for detecting a tilt signal corresponding to the amount of tilt between the upper surface of the recording medium mounting portion or the back surface of the recording surface of the optical disk recording medium and a predetermined reference surface; Corresponding to the jitter value measured by the jitter value measuring means, the recording medium based on a height difference of each point with respect to a reference point measured by the height difference measuring means and a tilt signal detected by the tilt signal detecting means. Inclination adjustment amount setting means for calculating an inclination adjustment amount between the upper surface of the mounting portion or the back surface of the recording surface of the optical disk recording medium and the reference surface; and an inclination adjustment based on the inclination adjustment amount obtained by the inclination adjustment amount setting means. Tilt adjustment means for performing
It is characterized by having. The pickup module, when recording and reproducing information on the optical recording medium,
It starts by performing so-called focusing and tracking, which aligns the focal length of the light beam with the track on the optical recording medium. Therefore, it is necessary to keep the inclination angle between the pickup module and the optical recording medium within a certain adjustment range during manufacturing. However, these adjustments in the production line are performed in a short time and can be performed by an unskilled worker, which is the basis for reducing the production cost and the production time. The present invention has been made in view of this, and is characterized in that the adjustment is completed as accurately as possible in a short time while being automated as much as possible. For this purpose, a height difference measuring means for measuring a height difference between the pickup module and the reference point, a tilt angle signal for detecting a tilt amount between the upper surface of the recording medium mounting portion or the back surface of the recording surface of the recording medium, and a predetermined reference surface. Detecting means, tilt adjustment amount setting means for calculating the tilt adjustment amount from the data thereof, and tilt adjustment means for performing tilt adjustment based on the tilt adjustment amount obtained therefrom, which are automatically integrated. And a device for adjusting the inclination angle. According to such an invention, the focus O due to the dimensional variation of the components of the pickup module or the like is obtained.
It is possible to eliminate the adjustment failure that does not result in N. That is, in the tilt angle adjustment, the possibility that the tilt angle cannot be adjusted because the focus is not turned on can be minimized, and the efficiency of the tilt angle adjustment process can be improved.

According to a second aspect of the present invention, the tilt signal detecting means includes:
It is also an effective means of the present invention that the present invention is configured by an optical sensor including a light emitting section and a plurality of light receiving sections. In order to detect the tilt angle, it is preferable that it can be performed as accurately as possible in a short time and that it can be electrically processed. As one of the methods, it is conceivable to detect the intensity of light with a photoelectric conversion element and detect an inclination angle therefrom. As a basic law of light,
Using the property that the incident angle and the reflection angle are equal, the reflected light from the object is received by a plurality of light receiving elements at a constant light emission angle, and the received light amount corresponding to the distribution of the received light is compared with a reference value. To find the tilt angle. According to this technical means, the inclination signal can be detected by one sensor, so that the number of parts of the apparatus can be reduced, and the cost of the apparatus can be reduced. Further, by using a plurality of light receiving portions of the sensor, the inclination angle of the recording medium or the like can be accurately detected. According to a third aspect of the present invention, the height difference measuring means functions as the tilt signal detecting means. The height difference measuring means includes a sensor for detecting a plurality of height differences. In other words, the value of the reference point is compared with the value of another sensor, and the difference between the values is determined based on the difference. The height difference is a distance difference from the reference point, and in other words, can be expressed as an inclination angle from the reference point. Therefore, if the distance from the reference point is known in advance,
The inclination at that time can be easily obtained by calculation. According to this technical means, the height difference measuring device can be used for detecting the tilt signal, the number of parts of the device can be reduced, and the cost of the device can be reduced. Further, since the inclination of the recording medium itself can be directly obtained, the inclination angle can be detected with high accuracy.

According to a fourth aspect of the present invention, the tilt signal detecting means is constituted by a plurality of sensors. According to this technical means, the accuracy of the inclination detection can be improved by using a plurality of sensors as the inclination signal detecting means in the first or third aspect of the present invention. A fifth aspect of the present invention is an effective means in which the back side of the recording surface of the recording medium is constituted by a reflection surface. In order to detect the tilt angle, the recording medium mounting portion supporting the center of the optical recording medium or the optical recording medium itself. In some cases, the optical recording medium is fixed to the recording medium mounting portion by a support member, so that the sensor may not be able to detect an accurate tilt angle due to the influence of the support member. Therefore, utilizing the fact that the back surface of the recording surface of the optical recording medium is formed of a reflective surface, the tilt angle is detected from the reflected light. According to such a technical means, when detecting the tilt angle of the recording medium using an optical sensor or the like, the tilt angle of the recording medium can be directly detected, so that the tilt angle detection accuracy is improved. In addition, it is possible to design a flexible inclination adjusting device regardless of the restriction on the installation location of the sensor. According to a sixth aspect of the present invention, it is effective that the tilt adjustment is terminated when the tilt signal detected by the tilt signal detecting means becomes larger than a predetermined set value. The adjustment process of the manufacturing process
As mentioned above, it must be done in the shortest possible time. For that purpose, it is important to automate the inspection process and to set inspection standards. The stricter the inspection standard, the higher the yield, but the longer the manufacturing time and the lower the manufacturing efficiency. Therefore, an adjustable range is set in advance, and a border line that can be reproduced by adjustment within this range is provided. As a result, it is possible to filter a component defect or a manufacturing defect from an initial stage. According to this technical means, the NG of the component mounted on the recording medium, which is a component, can be determined, so that component replacement can be performed in a minimum unit. In addition, since there is no useless adjustment time required for retrying and adjusting an NG product several times, manufacturing efficiency is improved. Claim 7
It is also an effective means of the present invention to terminate tilt adjustment when the jitter value measured by the jitter value measuring means becomes larger than a predetermined set value. After the tilt angle adjustment, the recording medium and the pickup are almost parallel,
If the pickup is composed of high-precision components, the jitter value measured after the tilt angle adjustment is close to the minimum value. Conversely, when the precision of the components used in the pickup is poor or when the actuator is installed at an angle, the jitter measurement value after adjusting the tilt angle becomes poor. By using this, it is possible to determine whether the pickup itself is good or bad. That is, the focus and tracking servo are turned on after the tilt angle adjustment, and if the jitter value measured first exceeds an arbitrary jitter threshold value, it is determined that the pickup component is defective, NG is displayed, and the tilt angle main adjustment is performed. (Obtain the minimum jitter value by changing the tilt angle) is not performed. According to such a technical means, since the NG of the pickup can be determined, the replacement of parts is the minimum unit. In addition, since there is no useless adjustment time required for retrying and adjusting an NG product several times, manufacturing efficiency is improved.

A pickup module of an optical disk information recording apparatus for measuring a jitter value based on a reproduced signal, calculating a tilt adjustment amount according to the jitter value, and performing tilt adjustment according to the tilt adjustment amount. In the tilt adjustment method, before measuring the jitter value, one point on a plurality of shafts on which the pickup module is mounted is used as a reference point, and one or more different points on the shaft having the reference point and the reference point are used as reference points. The height difference between a plurality of points on the shaft not having the reference point and the reference point is measured, and an inclination signal corresponding to the amount of inclination between the upper surface of the recording medium mounting portion or the back surface of the recording surface of the optical disk recording medium and a predetermined reference surface is calculated. Detected and corresponding to the measured jitter value, based on the height difference and the tilt signal, the upper surface of the recording medium mounting portion or the lower surface of the recording surface of the optical disk recording medium, The tilt adjustment of the serial reference plane is calculated, and performs the tilt adjustment according to the inclined angle adjustment amount. According to this invention, the same operation and effect as those of the first aspect can be obtained.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to an embodiment shown in the drawings. However, the components, types, combinations, shapes, relative arrangements, and the like described in this embodiment are not merely intended to limit the scope of the present invention but are merely illustrative examples unless otherwise specified. . FIG. 1 is a perspective view illustrating a configuration of a pickup module according to an embodiment of the present invention. The configuration of the pickup module includes a recording medium mounting section 1 having a flat portion on which a recording medium can be mounted and supported, and the flat portion rotates at a predetermined rotation speed by a control mechanism (not shown), and an LD (not shown).
A pickup 2 which is composed of a light emitting section, a lens optical system, a light receiving section, etc., and from which an optical signal can be obtained, and has a permanent magnet, a magnetic field generating coil, and an objective lens. By controlling the signals, the state of the magnetic field generation of the magnetic field generating coil changes, and the actuator 3 that can move the objective lens in the focus direction and the track direction, the reference positioning member 4, and the chassis 5 that is the main body of the pickup module And two shafts 6 installed in parallel so that the pickup can be held and moved, and a groove is carved like a screw in order to contact the shaft 6 and change the height position of the shaft. ,
It comprises a position adjusting member 7 that can change the height position of the shaft up and down by rotating in the forward and reverse directions. The shaft 6 has T0 as a reference position and T1
To T3 by three position adjusting members 7. When the position adjusting member 7 is (T1, T3), (T2, T3)
, The tilt angle of the pickup 2 can be changed in two directions. Here, the recording medium (not shown) is generally circular, and the recording medium mounting unit 1
When mounted on a recording medium, the angular direction formed by the height difference between (T0, T2) and (T1, T3) is an angular direction corresponding to the radial direction of the recording medium, and is called the radial direction.
The angle direction formed by the height difference between (T0, T1) and (T2, T3) is an angle direction corresponding to the tangential direction of the recording medium, and is called a tangential direction.

FIG. 2 is a configuration diagram of an inclination adjusting device according to an embodiment of the present invention. The same components are denoted by the same reference numerals, and duplicate description will be omitted. This configuration is based on the recording medium 8 mounted on the recording medium mounting unit 1.
The tilt signal detector 100 for detecting the tilt angle of the recording medium 8 with respect to the reference plane, and the rotatable bit 9 rotate the position adjustment member 7 to move the height of the shaft 6 up and down, thereby causing the pickup 2 to move. Inclination adjustment unit 110 for adjusting the inclination
And a height difference measuring unit 120 for measuring the height difference of the shaft 6 by a contact-type displacement sensor (not shown), and a radial inclination Θ and a tangential inclination Φ of the shaft 6 with respect to a reference plane are obtained. And a jitter value measuring unit 140 that measures a jitter value from a reproduced signal of information recorded on the recording medium 8. Note that the amount of change in the height direction of the position adjusting member 7 in one rotation of the reference surface bit 9 is known, and the height of the position adjusting member 7 can be controlled by the amount of rotation of the bit 9. Here, the inclination signal detection unit 100 mainly constitutes an inclination signal detection unit, the inclination adjustment unit 110 mainly constitutes an inclination adjustment unit, the elevation difference measurement unit 120 mainly constitutes an elevation difference measurement unit, and the inclination adjustment amount setting. The unit 130 mainly constitutes an inclination adjustment amount setting unit, and the jitter value measurement unit 140 mainly constitutes a jitter measurement unit.

FIG. 3 is a conceptual diagram for explaining a method of adjusting the tilt angle of the pickup 2. Normally, T0 to T3 are T0
Are set on the same plane with respect to the reference position, and this is set as a reference position. Here, when the pickup is tilted in the tangential direction described above, (T0, T1) and (T0, T1)
(2, T3). (T0, T1) are fixed to the same height indicated by a dashed line, and (T0, T1)
2, T3) can be moved. Where T2, T
When the position adjusting member in 3 rises or falls by an equal amount,
An angle in the tangential direction is formed with respect to the plane of T0 and T1 (see FIG. 3A). When tilting the pickup 2 in the radial direction described above, (T0, T0
2) and (T1, T3) are moved. (T
(0, T2) is fixed at the same height as indicated by a dashed line, and (T1, T3) is movable. Here, when the position adjusting member at T1 and T3 rises or falls by an equal amount, an angle in the radial direction is formed with respect to the plane where T0 and T2 exist (see FIG. 3B). Although T0 is a reference position and is fixed, T2 can be moved by the position adjusting member, so that when changing the angle in the radial direction, T0 and T2 do not necessarily have to be at the same height. This also makes it possible to change the angle in the radial direction after adjusting the angle in the tangential direction, or to change the angle in the tangential direction after adjusting the angle in the radial direction. The tilt angle of the pickup 3 can be changed to a position suitable for both initial and radial.

FIG. 4 is a perspective view of a height difference measuring device 200 in the height difference measuring section 120 of the present invention. A method for determining the height difference (shaft inclination) between two shafts on which a pickup is mounted will be described with reference to FIG. This configuration includes a contact-type displacement sensor 13 (S0 to S3) using a linear encoder,
A contact 14 whose tip changes in length according to the unevenness of the object (see FIG. 5), and a plane plate 1 for supporting them in a plane
5 is comprised. As shown in FIG.
A plurality of (for example, four S0 to S3) displacement sensors are provided on the flat plate 15 so as to be located on the shaft 6 of the book. The flat plate 15 is configured to move up and down while maintaining a posture parallel to a reference plane (not shown) on which the chassis 5 is mounted. A point (A0) at which a predetermined contact (for example, S0) contacts the shaft among the plurality of contacts is set as a reference point. Then, when the contacts of all the sensors come into contact with the shaft, the signals generated by the sensors (contact 1
4), the reference point (A0) where the contact on the shaft contacts and the other points (A1, A2, A3)
Find the height difference of each of. In this embodiment, a contact-type displacement sensor is used for the height difference measurement method. However, as shown in FIG. 6, an optical sensor or the like that detects a difference in distance based on a phase difference of a wave and obtains a height difference is used. May be used.

Next, a method for detecting the tilt angle of the recording medium 8 with respect to the reference surface by the tilt signal detecting unit 100 will be described. FIG.
FIG. 2 is a conceptual configuration diagram of a first embodiment of an inclination signal detection unit 100. As shown in the figure, a light emitting portion 16 and a plurality (4 in the figure)
) Is formed by an optical sensor including the light receiving unit 17 divided into two. The light receiving unit 17 is a photoelectric conversion element that generates a current proportional to the amount of light received. The light receiving section 17 is divided into four sections, and each section has similar photoelectric conversion characteristics.
FIG. 7A shows a state in which the reflection surface is parallel to the lower surface of the tilt signal detection unit 100 (the reflection surface at this time is assumed to be parallel to the reference surface). The emitted light forms a spot as shown in FIG. Therefore, as shown in FIG. 7D, the symbols (a, b, c, d) are assigned to the respective divided light receiving portions, and the currents generated from the respective portions are defined as (Ia, Ib, Ic, Id). For example, when the lower surface of the inclination detecting unit 100 and the reflecting surface are parallel, Ia = Ib and Ic = Id. However, FIG.
In the case where the reflection surface is inclined as shown in (a) (in the tangential direction), Ia = Ib, but Ic> Id.
Becomes When the reflecting surface is inclined as shown in FIG. 8B (in the radial direction), Ic = Id.
Ia> Ib. Therefore, by setting this reflection surface as the upper surface of the recording medium mounting portion and calculating the ratio of the magnitude of the current corresponding to the tilt angle in each divided portion in advance by calculation or measurement, the current actually detected in each divided portion is obtained. Conversely, the inclination of the reflection surface with respect to the reference surface can be obtained from the ratio of the values. That is, the inclination φ in the tangential direction can be obtained from the ratio of the magnitudes of Ic and Id, and the inclination θ in the radial direction can be obtained from the ratio of the magnitudes of Ia and Ib. Further, if the surface opposite to the recording surface of the recording medium 8 is made to reflect the finishing light to a mirror surface by aluminum evaporation or the like, the surface opposite to the recording surface of the recording medium 8 may be used as the reflection surface. (FIG. 17). This will be described in detail later.

Next, as a second embodiment of the tilt signal detecting means, a method using a height difference measuring device 200 for measuring the height difference at each point of the shaft shown in FIG. 4 will be described. FIG.
(A) is a perspective view for obtaining a height difference by the height difference measuring device 200. 4 points of the recording medium 8 (B0 to B3)
Is obtained by the same method as the method for obtaining the height difference of the shaft. Then, the inclination angle of the recording medium 8 with respect to the reference plane is obtained from the obtained height difference. Specifically, first, the centers of the four sensors (S0 to S3) installed in the height difference measuring device 200 are set on the center of the recording medium 8 (or the center of the recording medium mounting unit 1). Next, using one of the four points as a reference (for example, B0), the height difference between B0 and the other three points (B1, B2, B3) is determined. And B0
, A height difference H01 between a middle point B02 of B2 and a middle point B13 of B1 and B3. Assuming that the height differences between B0, B1, B2, and B3 are H1, H2, and H3, H01 can be obtained by the following equation. H01 = ((H3-H1) / 2)-(H2 / 2) Next, distances L01, B02 and B13 between B02 and B13.
From the height difference H01, the inclination θ in the radial direction can be obtained by the following equation (see FIG. 9B). θ = Arctan (H01 / L01) Similarly, when calculating the inclination in the tangential direction, first, the height difference H02 between the middle points B01, B2, and B3 of B0 and B1 is calculated by the following equation. H02 = ((H3-H2) / 2)-(H1 / 2) Also, if the distance L02 between B01 and B23 and the height difference H02 between B01 and B23 are known, the inclination φ in the tangential direction can be obtained by the following equation (FIG. 9 (c)). φ = Arctan (H02 / L02) Note that the inclination θ of the recording medium in the radial direction with respect to the reference plane
The calculation for calculating the inclination φ in the tangential direction may be performed by the inclination adjustment amount setting unit 130. In addition,
In this embodiment, the case where the height difference measuring device 200 for obtaining the shaft height difference is used has been described. However, the tilt angle detecting means is not limited thereto, and the height difference at three points C0 to C2 shown in FIG. A measuring device as required may be used, or a height difference of three or more points may be determined. Further, as shown in D0 to D2 of FIG. 10B, a measuring device for obtaining a height difference of a recording medium mounting portion may be used.

Next, the tilt adjustment amount setting section 130 will be described. As shown in FIG. 2, signals from the elevation difference measurement unit 120 and the inclination signal detection unit 100 are input to the inclination adjustment amount setting unit 130. As described above, the height difference measuring unit 120
Is a signal regarding the height difference between the two shafts 6 on which the pickup 2 is mounted with respect to the reference plane. Here, the height difference h01, A2, and A between A0 and A1 shown in FIG.
If the height difference h23 of 3 is different (h01−h23 ≠ 0), it means that the two shafts are in a torsion relationship. In this case, one of A1 to A3 must be adjusted so that the two shafts are parallel. Therefore, the adjustment amount is calculated by the inclination adjustment amount setting unit 130, and a signal of the calculated value is input to the inclination adjustment unit 110 to perform the adjustment. When the two shafts are in a parallel state, the radial tilt angle Θ and the tangential tilt angle Φ of these shafts can be obtained as follows (see FIGS. 11A and 11B). Θ = Acttan (h01 / L01) or Θ = Arctan (h23 / L23) Φ = Arctan (h02 / L02) or Φ = Arctan (h13 / L13) Is a signal of the tangential tilt angle φ and the radial tilt angle θ with respect to the tilt angle. By taking the difference between the two signals and the signal of the height difference signal (that is, the tangential tilt angle and the radial tilt angle of the shaft) of the shaft in a parallel state, the tilt of the two shafts 6 and the recording medium 8 can be determined. If the inclination is eliminated, that is, Θ−θ = 0 and Φ−φ = 0, the pickup 2 mounted on the two shafts 2 becomes parallel to the recording medium 8. Therefore, the rotation amount of the bit 9 is determined according to the value of Θ−θ or Φ−φ. Tilt adjustment unit 110
Then, the position adjustment member 7 can be displaced in accordance with the rotation amount of the bit 9 determined by the inclination adjustment amount setting unit 130 (see Japanese Patent Application Laid-Open No. 9-320214).

Here, the procedure for adjusting the tilt angle according to the present invention will be described below. The offset of each sensor of the height difference measuring device 200 in the height difference measuring unit 120 is adjusted. The height difference at each point on the shaft is determined by the height difference measuring device 200. When the signal of the height difference is input to the tilt adjustment amount setting unit 130 and it is determined that the two shafts are in a torsion relationship, the tilt adjustment amount setting unit 130 is set so that the two shafts are in a parallel state. Is used to calculate the amount of rotation of the position adjustment member 7, and the inclination adjustment unit 110 rotates the position adjustment member 7. The inclination adjustment amount setting unit 130 obtains the inclination Θ in the radial direction and the inclination Φ in the tangential direction of the shaft with respect to the reference plane, and records them in the memory in the inclination adjustment amount setting unit 130. The tilt signal detection unit 100 (and the tilt adjustment amount setting unit 13)
0), the inclination θ in the radial direction and the inclination φ in the tangential direction of the recording medium 8 (or the upper surface of the recording medium mounting portion) with respect to the reference plane are obtained. The difference between the inclination Θ in the radial direction and the inclination Φ in the tangential direction of the shaft with respect to the reference plane, and the difference between the inclination θ in the radial direction and the inclination φ in the tangential direction of the recording medium 8 (or the upper surface of the recording medium mounting portion) with respect to the reference plane. Then, an adjustment amount for making the recording medium 8 and the pickup 2 on the shaft 6 parallel is calculated. The adjustment amount obtained above is input to the inclination adjustment unit 110, and based on the input signal, the inclination adjustment unit 110 rotates the bit 9 until the position adjustment member 7 (T1 to T3) reaches a predetermined position. Thereby, the positional relationship between the recording medium 8 and the pickup 2 becomes parallel. Here, the information recorded for the first time is reproduced, and the jitter value measuring unit 14 is reproduced by a known method using the reproduced signal.
Measure the jitter value at 0. In accordance with the measured jitter value, the tilt adjustment amount is calculated by the tilt adjustment amount setting unit 130 by a conventional method (for example, Japanese Patent Laid-Open No. 9-320214), and the tilt adjustment unit 110 is calculated.
Fine adjustment of the tilt angle of the shaft with the final adjustment of the tilt angle.

Here, a problem when the recording medium 8 and the pickup 2 are not parallel will be described below. The divided light receiving elements (A,
B), an arbitrary signal is formed by the incidence of the LD emission laser reflected by the recording medium 8. Usually, by driving the actuator 3 mounted on the pickup 2,
The objective lens moves, and the LD emission laser focuses on the recording surface of the recording medium. At this time, the divided light receiving elements (A,
Since the light emitting laser is evenly incident on the boundary surface of B), if a difference signal between A and B is set, AB = 0. This AB is called a focus error signal. Here, when the actuator 3 moves up and down and the objective lens approaches or moves away from the recording medium, the ratio of the light incident on the light receiving elements A and B changes.
> 0, AB <0. FIG. 12 shows the characteristics of the focus error signal. The horizontal axis represents the displacement of the actuator, and the vertical axis represents the level of the focus error signal.

In a region A in FIG. 12 where the relationship between the actuator displacement and the focus error signal level is almost linear, the focus servo is turned on and the objective lens is displaced from the focus position (intersection 0 in FIG. 12). It is possible to drive the actuator to the in-focus position. In the other area B, it is difficult to drive to the in-focus position by the servo, and the focus servo is not turned on no matter how many times the operation is performed. Here, as shown in FIG. 13, when the recording medium 8 and the pickup 2 are parallel, the state of the area A in FIG. 12 is obtained. Becomes ON. On the other hand, as shown in FIG.
In the case where the actuator is installed at a relatively large inclination angle with respect to the pickup 2 due to variations in assembly or components, the state becomes as shown in a region B of FIG. 12 and the focus servo is not turned on even when the actuator 2 is moved. Unless the focus servo is turned on, a recording / reproducing signal cannot be obtained, so that characteristics such as a jitter value cannot be obtained.
Therefore, there occurs a problem that the tilt angle cannot be adjusted while measuring the jitter value. However, in the present invention, as described above, the tilt angle of the recording medium 8 (or the recording medium mounting portion) is measured in advance, the tilt angle of the pickup is set to be parallel to the tilt angle, and then the focus servo is turned ON. In addition, it is possible to eliminate the inability to adjust the tilt angle so that the focus is not turned on due to variations in the dimensions of the pickup module components (see FIG. 15).

FIG. 16 shows a state in which the recording medium 8 is fixed by a recording medium fixing member 11 made of resin. Reference numeral 10 denotes a sensor for detecting an inclination signal, which includes a light emitting unit and a light receiving unit, and has a structure for detecting displacement in a state of receiving light. Here, the recording medium fixing member 11 is used to prevent the recording medium 8 from dropping from the recording medium mounting portion 1. However, since the recording medium fixing member 11 is made of resin, the light of the sensor 10 cannot be sufficiently reflected, and the inclination angle is detected. Can not do it. Also,
Since the inclination angle on the recording medium fixing member 11 is detected, for example, when there is a gap between the recording medium fixing member 11 and the recording medium 8, the inclination angle of the recording medium mounting portion 1 or the inclination of the recording medium 8 is determined. There is a possibility that a problem of measuring a tilt angle different from the tilt angle may occur. However, the recording medium fixing member 11 is necessary in consideration of the stability when the recording medium 8 rotates. Therefore, in the present invention, as shown in FIG. 17, the recording medium used at the time of adjusting the tilt angle is the organic recording layer 12a,
By using the one composed of the metal reflection surface 12b,
Even when the inclination angle of the recording medium itself is detected and the recording medium fixing member 11 is used, it is possible to set the inclination angle at which the focus is turned ON. Further, since the tilt angle measurement area can be secured in a wider area than the recording medium mounting section 1, the position of the sensor 10 for tilt angle measurement can be freely changed, which is advantageous from the viewpoint of a margin of the apparatus layout.

FIG. 18 shows the tilt adjustment range in the radial and tangential directions at the time of tilt adjustment. In the above description, the defect of the pickup is mainly determined. However, there are cases where the inclination angle of the recording medium mounting member has an abnormal value due to a component defect. Therefore, as shown in FIG. 18, upper and lower threshold values are set for each of the radial and tangential tilt angles obtained by the tilt angle adjustment, and if the tilt angle is within the threshold value (the hatched portion in the figure), the tilt angle adjustment is OK. And if the inclination angle exceeds the threshold value, N
G is displayed to replace the recording medium mounting member.
Here, A1, A2, B1, and B2 are all set values, and are set in accordance with the pickup module that performs the tilt adjustment. Accordingly, the NG of the recording medium mounting member, which is a component of the pickup module, can be determined in a short time, so that it is not necessary to analyze which component caused the NG at the time of the tilt angle adjustment NG, and to replace the component. Is the minimum unit. In addition, since there is no useless adjustment time required for retrying and adjusting an NG product several times, manufacturing efficiency is improved.

FIG. 19 is a graph showing the jitter value obtained when the tilt angle is changed while the focus servo and the tracking servo are on. Normally, an appropriate tilt angle of the pickup is obtained as a tilt angle (m) with respect to the jitter minimum value (J) by obtaining a minimum jitter value (J) when the tilt angle is changed by quadratic curve approximation or the like. By the way, after the tilt angle adjustment, the recording medium and the pickup are in a substantially parallel state, and if the pickup is formed of high-precision parts, the jitter value measured after the tilt angle adjustment is close to the minimum value. . Conversely, when the precision of the components used in the pickup is poor or when the actuator is installed at an angle, the jitter measurement value after adjusting the tilt angle becomes poor. By using this, it is possible to determine whether the pickup itself is good or bad. That is, after adjusting the tilt angle, the focus and tracking servo are turned on. If the jitter value measured first exceeds an arbitrary jitter threshold value Jm, it is determined that the pickup component is defective, and N
G is displayed to prevent the tilt main adjustment (obtaining the minimum jitter value by changing the tilt angle). As a result, the NG of the pickup, which is a component part, can be determined in a short time, so that it is not necessary to analyze which component caused the NG at the time of the tilt adjustment NG, and the component replacement can be performed in a minimum unit. . In addition, since the cause component can be specified, useless adjustment time for producing a non-defective product while retrying several times in the actual tilt angle adjustment is eliminated, and the manufacturing efficiency is improved.

[0023]

As described above, according to the present invention, the first and eighth aspects can eliminate the inability to adjust the focus without turning on the focus due to dimensional variations of the components of the pickup module. That is, in the tilt adjustment, the possibility that the tilt adjustment cannot be performed because the focus is not turned on can be suppressed as much as possible, and the efficiency of the tilt adjustment process can be improved. According to the second aspect, since the inclination signal can be detected by one sensor, the number of parts of the apparatus can be reduced and the cost of the apparatus can be reduced. Further, by using a plurality of light receiving portions of the sensor, the inclination angle of the recording medium or the like can be accurately detected. According to the third aspect, the height difference measuring device can be used for detecting the tilt signal, the number of parts of the device can be reduced, and the cost of the device can be reduced. Further, since the inclination of the recording medium itself can be directly obtained, the inclination angle can be detected with high accuracy. According to a fourth aspect of the present invention, by using a plurality of sensors as the tilt signal detecting means in the first or third aspect of the invention, the accuracy of the tilt angle detection can be improved. According to the fifth aspect, when the inclination of the recording medium is detected using an optical sensor or the like, the inclination of the recording medium can be directly detected, and the accuracy of the inclination detection is improved. In addition, it is possible to design a flexible inclination adjusting device regardless of the restriction on the installation location of the sensor. According to the sixth aspect, since the NG of the component mounted on the recording medium, which is a component, can be determined, component replacement can be performed in a minimum unit. In addition, since there is no useless adjustment time required for retrying and adjusting an NG product several times, manufacturing efficiency is improved. According to the seventh aspect, since the NG of the pickup can be determined, replacement of parts is the minimum unit. Also, N
Since there is no useless adjustment time for retrying and adjusting the G product several times, manufacturing efficiency is improved.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating a configuration of a pickup module according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of an inclination adjusting device according to an embodiment of the present invention.

FIG. 3 is a conceptual diagram for explaining a method of adjusting the tilt angle of a pickup according to the present invention.

FIG. 4 is a perspective view of a height difference measuring device in the height difference measuring section of the present invention.

FIG. 5 is a diagram for explaining the operation of the displacement sensor of the present invention.

FIG. 6 is a diagram for explaining an operation of an optical sensor as another embodiment of the displacement sensor.

FIG. 7 is a conceptual configuration diagram of a first embodiment of a tilt signal detection unit of the present invention.

FIG. 8 is a diagram illustrating a light distribution of a light receiving unit according to the present invention.

FIG. 9 is a perspective view for obtaining a height difference by the height difference measuring device of the present invention.

FIG. 10 is a plan view for obtaining a height difference from three height differences according to the present invention.

FIG. 11 is a diagram for explaining a method of calculating an adjustment amount by the tilt adjustment amount setting unit according to the present invention.

FIG. 12 is a diagram showing characteristics of a focus error signal.

FIG. 13 is a diagram illustrating a positional relationship (1) between a recording medium and a pickup.

FIG. 14 is a diagram illustrating a positional relationship (2) between a recording medium and a pickup.

FIG. 15 is a diagram illustrating a positional relationship (3) between a recording medium and a pickup.

FIG. 16 is a configuration diagram illustrating a state in which the recording medium is fixed by a recording medium fixing member made of resin when tilt angle detection is performed.

FIG. 17 is a configuration diagram at the time of tilt angle detection showing a state in which a recording medium having a reflection surface is fixed by a recording medium fixing member made of resin.

FIG. 18 is a focus error signal characteristic diagram showing a tilt angle adjustment range in a radial direction and a tangential direction at the time of tilt angle adjustment, at a reference position and a tilt angle shift position.

FIG. 19 is a graph showing a jitter value obtained when the tilt angle is changed in a state where the focus servo is on and the tracking servo is on.

FIG. 20 is a plan view showing a configuration of an optical disk device in a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Recording medium mounting part 2 Pickup 5 Chassis 6 Shaft 7 Position adjustment member 8 Recording medium 9 Bit 100 Tilt signal detecting part 110 Tilt adjusting part 120 Height difference measuring part 130 Tilt adjusting amount setting part 140 Jitter value measuring part

Claims (8)

[Claims] 1. A tilt adjustment device for a pickup module of an optical disc information recording device, which calculates a tilt adjustment amount according to a jitter value measured from a reproduction signal and performs tilt adjustment based on the tilt adjustment amount. A jitter value measuring means for measuring a jitter value based on the reproduced signal of the above, and a specific point on a plurality of shafts on which the pickup module is mounted as a reference point, and at least one other different point on the shaft having the reference point. Height difference measuring means for measuring the height difference between the reference point and a plurality of points on the shaft not having the reference point and the reference point, and a predetermined distance between the upper surface of the recording medium mounting portion or the back surface of the recording surface of the optical disk recording medium. Tilt signal detecting means for detecting a tilt signal corresponding to the amount of tilt with respect to the reference plane, and corresponding to the jitter value measured by the jitter value measuring means. Based on the height difference of each point with respect to the reference point measured by the height difference measuring means and the tilt signal detected by the tilt signal detecting means, the upper surface of the recording medium mounting portion or the back surface of the recording surface of the optical disk recording medium and the reference An inclination adjustment amount setting means for calculating an inclination adjustment amount with respect to the surface; and an inclination adjustment means for performing an inclination adjustment based on the inclination adjustment amount obtained by the inclination adjustment amount setting means. Adjustment device. 2. The tilt adjusting device according to claim 1, wherein said tilt signal detecting means comprises an optical sensor having one light emitting portion and a plurality of light receiving portions. 3. The tilt adjusting device according to claim 1, wherein said height difference measuring means functions as said tilt signal detecting means. 4. The tilt adjusting device according to claim 2, wherein said tilt signal detecting means comprises a plurality of sensors. 5. The tilt angle adjusting device according to claim 1, wherein a back surface of the recording surface of the recording medium is constituted by a reflection surface. 6. The tilt adjustment device according to claim 1, wherein the tilt adjustment is terminated when the tilt signal detected by the tilt signal detection means becomes larger than a predetermined set value. . 7. The tilt adjustment device according to claim 1, wherein the tilt adjustment is terminated when the jitter value measured by the jitter value measurement means is larger than a predetermined set value. 8. A jitter value is measured based on a reproduced signal,
A tilt adjustment method for a pickup module of an optical disc information recording apparatus that calculates a tilt adjustment amount according to the jitter value and performs tilt adjustment according to the tilt adjustment amount, wherein a plurality of pickup modules are mounted before the jitter value measurement. A reference point on a specific point on the shaft having the reference point, and a height difference between the reference point and a plurality of different one or more other points on the shaft having the reference point and a plurality of points on a shaft not having the reference point Is measured, and a tilt signal corresponding to the amount of tilt between the upper surface of the recording medium mounting portion or the back surface of the recording surface of the optical disk recording medium and a predetermined reference plane is detected. In accordance with the measured jitter value, the height difference and Calculating an inclination adjustment amount between the upper surface of the recording medium mounting portion or the back surface of the recording surface of the optical disc recording medium and the reference surface based on the inclination signal; A tilt adjustment method, which comprises adjusting the angle.