JP3871325B2 - Objective lens tilt adjusting method of optical pickup device, objective lens tilt adjusting device of optical pickup device, and manufacturing method of optical pickup device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for adjusting the tilt of an objective lens of an optical pickup device and the like that can reduce costs and shorten adjustment time.
[0002]
[Prior art]
The objective lens tilt adjusting device adjusts an objective lens provided in an optical pickup device mounted on a CD (Compact Disk), a DVD (Digital Versatile Disk), etc., and its overall configuration is shown in FIG. Has been.
First, in the pickup device 100, the light emitted from the light projecting element 101 is converted into parallel light by the collimating lens 104 via the quarter-wave plate 102 and the mirror 103, and then the objective lens 106 attached to the actuator 105. Irradiate outside after making convergent light.
[0003]
On the other hand, in the objective lens tilt adjusting apparatus 200, the convergent light from the objective lens 106 is transmitted through the pseudo disk 201, and then converted into parallel light by the objective lens 202, and again through the convergent lens 203, the relay lens 204, and the ND filter 205. Let it be convergent light. Then, the convergent light is applied to the imaging surface of the CCD 206 (imaging means). Note that it is necessary to focus the convergent light from the objective lens 106 on the surface of the pseudo disk 201. To do so, the pseudo disk 201 and the objective lens 202 are provided so as to be movable in the direction of the optical axis LC. Yes.
[0004]
The imaging surface of the CCD 206 is irradiated with primary light, secondary light,... Concentrically around the beam spot B (zero order light). Here, when the objective lens 106 is tilted with respect to the optical axis LC, coma aberration occurs and the luminance distribution in the primary light, secondary light,... The direction becomes brighter and the opposite direction becomes darker (see FIG. 11). Therefore, conventionally, the area center position of the beam spot B and the area center position of the irradiation region of the primary light, the secondary light,... Are calculated, respectively, so that the positions coincide with each other (in practice, By adjusting the tilt of the objective lens 106 so that the brightness of the primary light is uniform, the objective lens 106 is positioned at a correct position where no coma aberration occurs (a position where the central axis of the objective lens coincides with the optical axis LC). ) (See Patent Document 1 below).
[0005]
[Patent Document 1]
JP 10-49877 A
[0006]
[Problems to be solved by the invention]
However, in the configuration as described above, it is necessary to capture the zero-order light of the beam spot B and the other primary light as a distinguishable irradiation image on the CCD 206. High-precision tilt adjustment cannot be performed unless the objective lens adjustment device 200 is configured with a small number of high-quality optical systems. Even if the positional relationship is such that the light that forms the maximum luminance point of the beam spot B on the CCD 206 passes through a path deviated from the optical axis of the optical system (an optical path in which almost no coma aberration occurs). In order to obtain an accurate irradiation image in which the inclination of the lens 106 is reflected, it is necessary that the lenses constituting the optical system of the objective lens inclination adjusting apparatus 200 are also expensive with less aberration.
[0007]
In addition, the optical pickup device as described above is flown on the production line and the objective lens tilt is adjusted sequentially. During the adjustment of the objective lens tilt from the nature of precise measurement. Has temporarily stopped the flow of the production line. On the other hand, in order to shorten the stop time of the production line as much as possible and improve productivity, there is a demand for shortening the time for adjusting the tilt of the objective lens 106.
[0008]
The present invention has been completed based on the above circumstances, and an objective lens tilt adjustment method for an optical pickup device and an optical pickup device capable of reducing the tilt adjustment time while reducing costs. It is an object of the present invention to provide an objective lens tilt adjusting device and an optical pickup device manufacturing method.
[0009]
[Means for Solving the Problems]
The inventors of the present invention have intensively studied to develop an objective lens tilt adjusting device capable of reducing the cost. As a result, the inventors have found the following knowledge and completed the present invention.
When the change in the amount of light received at the maximum brightness point position of the beam spot on the imaging surface was examined, if the tilt of the objective lens is 0 ° when the beam quality is the best (minimum coma aberration), the beam is tilted with the objective lens. It was discovered that when the quality deteriorates (coma aberration increases), the amount of light received at the maximum luminance point of the beam spot decreases, and the relationship of the amount of light received with respect to each tilt angle (tilt angle) of the objective lens is a quadratic curve. I found it to be represented.
[0010]
As a means for achieving the above object, the invention of claim 1 is directed to an optical pickup device comprising a light source and an objective lens for converging light emitted from the light source and emitting the light to the outside. The light emitted from the objective lens is incident on an optical adjusting device including a lens optical system and an imaging unit, and is irradiated onto the imaging surface of the imaging unit through the lens optical system. A spot is formed, and the optical pickup device or the optical adjustment device is moved so that the maximum luminance point of the beam spot coincides with the intersection point through which the optical axis of the lens optical system passes, and the inclination angle of the objective lens can be taken. Of these, a first tilt angle in one direction with respect to the optical axis, a second tilt angle in the opposite direction, and a third tilt angle different from the first and second tilt angles, The amount of light received at the maximum luminance point is sampled, a quadratic curve is calculated based on the amount of light received at the maximum luminance point at these inclination angles, and the amount of light received at the maximum luminance point for each inclination angle of the objective lens is calculated, Of these, the objective lens is adjusted to an inclination angle that maximizes the amount of light received at the maximum luminance point.
[0011]
According to a second aspect of the present invention, in the first aspect, the first tilt angle is a maximum tilt angle in the one direction, and the second tilt angle is a maximum tilt angle in the opposite direction. Has characteristics.
[0012]
According to a third aspect of the present invention, there is provided an optical pickup device comprising a light source and an objective lens that converges and emits light from the light source to the outside. An adjustment stage for fixing the optical pickup device, a lens tilt angle varying mechanism for changing the tilt of the objective lens, and irradiating light emitted from the objective lens of the pickup device through a lens optical system. An imaging means in which a beam spot is formed on the imaging surface; and a stage drive mechanism that moves the adjustment stage so that light at the maximum luminance point of the beam spot coincides with an intersection point through which the optical axis of the lens optical system passes; Of the tilt angles that the objective lens can take, a first tilt angle in one direction with respect to the optical axis and a second tilt angle in the opposite direction. Sampling means for sampling the amount of light received at the maximum luminance point at an inclination angle and a third inclination angle different from the first and second inclination angles, and the maximum luminance point at the first, second, and third inclination angles. And calculating means for calculating a quadratic curve based on the received light amount and calculating the received light amount at the maximum luminance point with respect to each inclination angle of the objective lens, and an inclination angle at which the received light amount at the maximum luminance point is maximized. And a driving means for adjusting the lens tilting variable mechanism.
[0013]
According to a fourth aspect of the present invention, in the first aspect, the first tilt angle is a maximum tilt angle in the one direction, and the second tilt angle is a maximum tilt angle in the opposite direction. Has characteristics.
[0014]
The invention according to claim 5 is a method for adjusting the tilt of the objective lens in an optical pickup device comprising a light source and an objective lens for converging the light from the light source and emitting the same to the outside. The light emitted from the lens is incident on an optical adjusting device composed of a lens optical system and an imaging means, and a beam spot is formed by irradiating the imaging surface of the imaging means through the lens optical system. The maximum brightness of the beam spot While moving the optical pickup device or the optical adjustment device so that the point coincides with the intersection point through which the optical axis of the lens optical system passes, the inclination angle of the objective lens can be in one direction with respect to the optical axis. The received light amount of the maximum brightness point at the first tilt angle, the second tilt angle in the opposite direction, and the third tilt angle different from the first and second tilt angles is sampled. And calculating a quadratic curve based on the amount of light received at the maximum luminance point at these inclination angles to calculate the amount of light received at the maximum luminance point for each inclination angle of the objective lens, of which the amount of light received at the maximum luminance point is It is characterized in that it includes a step of adjusting the objective lens to a maximum tilt angle.
[0015]
According to a sixth aspect of the present invention, in the first aspect, the first tilt angle is a maximum tilt angle in the one direction, and the second tilt angle is a maximum tilt angle in the opposite direction. Has characteristics.
[0016]
Operation and effect of the invention
In the conventional method of adjusting the tilt of the objective lens, for example, the tilt of the objective lens is set so that the brightness distribution of the primary light in a ring shape formed around the beam spot is uniform. . This is because if the central axis of the objective lens and the central axis of the light from the light source (actually parallel light) deviate, coma aberration occurs and the brightness of the primary light becomes non-uniform. Therefore, the inclination of the objective lens can be corrected by adjusting the inclination of the objective lens so that the brightness of the primary light is uniform in each part.
Here, the non-uniformity of the brightness of the primary light must reflect only the degree of coma generated by the objective lens. Therefore, the coma aberration generated by the lens provided in the device for adjusting the tilt of the objective lens (objective lens tilt adjusting device) must be eliminated, which requires high-quality optical parts and high assembly accuracy. There has been a problem that the objective lens tilt adjustment device is expensive.
In an actual objective lens tilt adjustment device, light from the objective lens of the optical pickup device is irradiated onto the imaging surface through a lens optical system composed of a plurality of optical components such as lenses. And the optical axis of the lens optical system.
[0017]
In view of such circumstances, in the present invention, while moving the adjustment stage so that the maximum luminance point of the beam spot coincides with the intersection of the imaging surface through which the optical axis of the lens optical system passes, Among them, the inclination of the objective lens is adjusted so that the amount of light received at the maximum luminance point of the laser spot becomes maximum. By doing so, the quality and assembly accuracy of the lens optical system can be moderated, so that the cost of the apparatus can be reduced. Furthermore, coma aberration generated by the lens optical system is minimized, and more accurate tilt adjustment is performed.
Specific objective lens adjustment methods include a first tilt angle in one direction with respect to the optical axis, a second tilt angle in the opposite direction, and the first and first tilt angles that can be taken by the objective lens. The amount of light received at the maximum brightness point at a third tilt angle different from the tilt angle of 2 is sampled, and a quadratic curve is calculated based on the amount of light received at the maximum brightness point at these tilt angles, with respect to each tilt angle of the objective lens. The amount of light received at the maximum luminance point is calculated, and the objective lens is adjusted to an inclination angle that maximizes the amount of light received at the maximum luminance point. Thus, the objective lens can be adjusted to the correct posture without sampling all the tilt angles that the objective lens can take, and thus the adjustment time can be shortened (Claim 1, Claim 3 and Claim 3). 5 invention).
[0018]
Here, as a method of calculating the quadratic curve, by using the fact that a quadratic function is obtained from the coordinates (tilt angle, received light amount) of three points, the objective light is detected from the received light amount of the maximum luminance point with respect to the three kinds of tilt angles. The amount of light received for each tilt angle of the lens can be obtained. The same applies to the least square method using a quadratic function.
[0019]
In addition, when the least square method is used, the received light amount at a tilt angle at least larger than the tilt angle and the received light amount at a small tilt angle are sampled with respect to the tilt angle at which the received light amount at the maximum luminance point is predicted to be the maximum. Is desirable. Therefore, the most desirable quadratic curve can be obtained by sampling the amount of light received at the maximum tilt angle in one direction and the amount of light received at the maximum tilt angle in the opposite direction, and the tilt adjustment of the objective lens can be performed more reliably. (Invention of Claim 2, Claim 4 and Claim 6).
[0020]
DETAILED DESCRIPTION OF THE INVENTION
<First Embodiment>
An embodiment of an objective lens tilt adjusting apparatus according to the present invention will be described with reference to FIGS. The objective lens tilt adjusting device of the present embodiment detects and adjusts the tilt of an objective lens provided in an optical pickup device mounted on a CD (CompactDisk), a DVD (Digital VersatileDisk) or the like. In FIG. 1, the horizontal direction in the drawing is defined as the X axis, the direction orthogonal to the drawing is defined as the Y axis, the vertical direction in the drawing is defined as the Z axis, and the center of the objective lens 15 is defined as the origin.
[0021]
As shown in FIG. 1, the optical pickup device 1 includes a light projecting / receiving element 11 (corresponding to a “light source” recited in the claims), a quarter-wave plate 12, a reflecting mirror 13, a collimating lens 14, an objective. The device 15 includes a lens 15 and a support member 16 capable of adjusting the angle supported by the objective lens 15, and the apparatus 1 is fixed to the adjustment stage 29b. Then, the light from the light projecting / receiving element 11 is converted into parallel light by passing through the collimating lens 14 via the quarter-wave plate 12 and the reflecting mirror 13, and then passing through the objective lens 15 to be externally converged light. It is comprised so that it may radiate | emit to.
[0022]
The support member 16 (corresponding to the “lens tilt angle varying mechanism” described in the claims) is rotated in one direction by rotating one of two screws (not shown) provided in the support member 16 (centered on the X axis). The objective lens 15 is rotated in the direction (in which the objective lens 15 is rotated), and the other is turned to rotate in the θY direction (the direction in which the objective lens 15 is rotated around the Y axis). With the rotation of 16, the objective lens 15 is also rotated. Further, these screws are rotated by a driver 28a provided in driver driving means 28 described later.
[0023]
The adjustment stage 29b is provided with a servo mechanism (not shown). When the servo drive signal Sd is received from the stage control means 30 (corresponding to the “stage drive mechanism” described in the claims) described later, XY is provided. The plane is moved two-dimensionally. As described above, when the adjustment stage 29b moves, the optical pickup apparatus 1 also moves on the XY plane.
[0024]
The objective lens tilt adjusting device 2 is configured to receive convergent light from the optical pickup device 1. Specifically, the convergent light emitted from the objective lens 15 is transmitted through the pseudo disk 21 (spherical aberration correction plate) and converted into parallel light through the objective lens 22, and then the parallel light is converted into the convergent lens 23, the relay lens 24, and the ND filter. The imaging surface of the CCD 26 (charge coupled device, corresponding to “imaging means” recited in the claims) is irradiated through a lens optical system such as 25. Further, the CCD 26 is configured to output an imaging signal Sa composed of a pulse train corresponding to the amount of light received by each pixel constituting the imaging surface, and this imaging signal Sa is transmitted to the CPU 27a.
The objective lens 22 is movable in the Z-axis direction, and the position of the objective lens 22 is adjusted so that the focal point of the convergent light coincides with the imaging surface of the CCD 26. Further, the optical axis of the lens optical system and the center of the imaging surface of the CCD 26 are configured to coincide on the Z axis. Therefore, the center of the imaging surface corresponds to “the intersection where the optical axis of the lens optical system passes” (hereinafter referred to as “origin O”). The lens optical system and the CCD 26 (reference numeral 20) correspond to the configuration of the “optical adjustment device” recited in the claims.
[0025]
The CPU 27 transmits a driver drive signal Sb and a stage drive signal Sc to the driver drive means 28 and the stage control means 29a, respectively, based on the received imaging signal Sa. A predetermined storage area is secured in the memory 27b provided in the CPU 27a.
The driver driving means 28 is configured to turn a screw provided on the support member 16 by the driver 28a based on the driver driving signal Sb from the CPU 27a, and the stage control means 29a is a stage driving signal Sc from the CPU 27a. Is configured to transmit a servo drive signal Sd to the servo mechanism of the adjustment stage 29b.
[0026]
The configuration of the present embodiment is as described above, and the operation will be described focusing on the processing of the CPU 27a.
The light emitted from the light projecting / receiving element 11 of the optical pickup device 1 is irradiated onto the imaging surface of the CCD 26 as described above, and as shown in FIG. 2, the CPU 27a performs an inclination adjustment routine (step S1) in the θX direction. , And FIG. 3) and the inclination adjustment routine in the θY direction (see step S2, FIG. 4).
[0027]
<Inclination adjustment in the θX direction>
First, in this process and the tilt adjustment process in the θY direction, the tilt angle of the objective lens 15 before sending the driver drive signal Sb (initial state) is assumed to be 0 °, and the tilt angle with respect to the initial state is shown below.
As shown in FIGS. 3 and 8, by first outputting a driver driving signal Sb to the driver driving means 28, when one screw of the support member 16 is fully rotated in one rotation direction, the objective lens 15 is moved. It is tilted to the maximum tilt angle θX1 (θX (max)) in the + θX direction (step S101). Then, the received light amount / tilt angle acquisition routine (step S3, see FIG. 5) is performed.
[0028]
As shown in FIG. 5, the CPU 27a calculates the amount of light received by each pixel based on the imaging signal Sa received from the CCD 26 (step S301). At this time, if it is determined that the received light amount of the center pixel (pixel corresponding to the origin O) on the imaging surface is the maximum among all the pixels (Yes in step S302), the received light amount L1 and the inclination angle θX1 are set as follows. The memory 27b is stored (step S303).
[0029]
On the contrary, when the light reception amount of the central pixel is not determined to be the maximum (No in step S302), the distances (ΔX, ΔY) between the pixel having the maximum light reception amount and the central pixel are calculated ( In step S304, a control signal Sc corresponding to this distance is output to the stage control means 29a (step S305). Then, a servo drive signal Sd is output from the stage control means 29a to the servo mechanism, and the servo mechanism moves the adjustment stage 29b by (ΔX, ΔY). Along with this, the objective lens 15 moves and the beam spot B is irradiated to the central portion (origin O) of the imaging surface, and as a result, the central pixel is set to the maximum light receiving amount (see FIG. 7). As a result, the “maximum luminance point of the beam spot can be made to coincide with the intersection point through which the optical axis of the lens optical system passes” in the present invention. Then, the received light amount L1 and the inclination angle θX1 of the central pixel at this time are stored in a predetermined area of the memory 27b (step S303).
[0030]
Next, in step S102, by outputting a driver driving signal Sb to the driver driving means 28, when one screw of the support member 16 is rotated by a predetermined number of rotations in the opposite rotation direction, the objective lens 15 is -θX. Rotate in the direction to be the tilt angle θX2 (step S102). Then, the received light amount acquisition routine is performed (step S3). At this time, since the objective lens 15 is tilted, the maximum luminance point R of the beam spot B is shifted from the origin O of the CCD 26, so steps S304 and S305 are executed in the received light amount / tilt angle acquisition routine (step S3). The maximum luminance point R is located at the origin O. Then, the received light amount L2 and the inclination angle θX2 of the central pixel are stored in the memory 27b (step S303).
[0031]
In step S103, by outputting the driver driving signal Sb to the driver driving means 28, when one screw of the support member 16 is fully rotated in the opposite rotational direction, the objective lens 15 is maximized in the -θX direction. The inclination angle θX3 (−θX (max)) is set (step S102). Then, the received light amount / tilt angle acquisition routine is performed (step S3), and the received light amount L3 and the tilt angle θX3 of the central pixel are stored in the memory 27b (step S303). By performing the above processing, the “first inclination angle in one direction with respect to the optical axis among the inclination angles that can be taken by the objective lens”, the second inclination angle in the opposite direction, and the first and The amount of light received at the maximum luminance point at a third tilt angle different from the second tilt angle can be “sampled”. Thereafter, a curve interpolation routine (step S4) is executed.
[0032]
First, a quadratic curve C is obtained by the least square method (curve interpolation) from the received light amounts (L1, L2, L3) at the inclination angles (θX1, θX2, θX3) sampled by the above processing (step S401). Of this quadratic curve C, the inclination angle “θX0” of the objective lens 15 that maximizes the amount of received light L is calculated (step S402). In order to set the inclination angle of the objective lens 15 to “θX0”, The rotation angle ΔθXh of the objective lens 15 is calculated from the tilt angle θX3 (step S403). Then, in step S104, the objective lens 15 is rotated by ΔθXh by sending the driver drive signal Sb. Therefore, the tilt angle θX0 is theoretically a correct tilt angle that minimizes coma aberration.
The tilt angles θX1, θX2, and θX3 correspond to the “first, second, and third tilt angles” of the present invention.
[0033]
<Adjustment in θY direction>
As shown in FIGS. 3 and 8, by first outputting a driver drive signal Sb to the driver drive means 28, when the other screw of the support member 16 is fully rotated in one rotation direction, the objective lens 15 is moved. It is tilted to the maximum tilt angle θY1 (θY (max)) in the + θY direction (step S201). Then, the received light amount / tilt angle acquisition routine is performed (step S3), and the received light amount L1 and tilt angle θY1 of the central pixel are stored in the memory 27b (step S303).
[0034]
Next, in step S202, by outputting the driver driving signal Sb to the driver driving means 28, when the other screw of the support member 16 is rotated by a predetermined number of rotations in the opposite rotation direction, the objective lens 15 is -ΔθY. Inclined to an inclination angle θY2 (step S202). Then, the received light amount / tilt angle acquisition routine is performed (step S3), and the received light amount L2 and the tilt angle θY2 of the central pixel are stored in the memory 27b (step S303).
[0035]
In step S103, by outputting the driver drive signal Sb to the driver drive means 28, when the other screw of the support member is fully rotated in the opposite rotation direction, the objective lens 15 is tilted to the maximum inclination angle in the -θY direction. θY3 (−θY (max)) is set (step S202). Then, the received light amount / tilt angle acquisition routine is performed (step S3), and the received light amount L3 and the tilt angle θY3 of the central pixel are stored in the memory 27b (step S303). Thereafter, a curve interpolation routine (step S4) is executed.
[0036]
First, a quadratic curve C is obtained from the received light amounts (L1, L2, L3) at the sampled inclination angles (θY1, θY2, θY3) by the method of least squares (curve interpolation) (step S401). Of the quadratic curve C, the inclination angle “θY0” of the objective lens 15 that maximizes the amount of received light is calculated (step S402). In order to set the inclination angle of the objective lens to “θY0”, the inclination angle θY0 and the current inclination angle θY3 are Is used to calculate the rotation angle ΔθYh of the objective lens (step S403). In step S204, the objective lens is rotated by ΔθYh by sending a driver drive signal Sb. Therefore, the tilt angle θY0 is theoretically a correct tilt angle that minimizes coma aberration.
The tilt angles θY1, θY2, and θY3 correspond to “first, second, and third tilt angles” of the present invention.
[0037]
From the above operation, the CPU 27a is configured as “sampling means” and “calculation means” recited in the claims, and the CPU 27a and the driver driving means 28 are configured as “drive means” recited in the claims. it is obvious.
[0038]
FIG. 9 is a graph showing the relationship between the amount of received light and coma aberration with respect to the inclination angle of the objective lens 15 in the θX direction. As is apparent from this graph, the amount of light received by the central pixel on the imaging surface is maximized when the inclination of the objective lens 15 is 0 °, that is, when the objective lens 15 is at an angle at which coma aberration is minimized. . Therefore, by performing the above processing, the objective lens 15 can be reliably adjusted to the correct posture (tilt angle at which coma aberration is minimized) and the adjustment time can be shortened extremely.
[0039]
Thus, in this embodiment, since the inclination of the objective lens 15 is adjusted based on the amount of light received on the imaging surface, the inclination is adjusted based on the brightness balance of the optical image on the conventional imaging surface. Thus, high-precision optical components and high assembly accuracy are not required to suppress the occurrence of coma aberration in the optical system in the apparatus 2, and the apparatus can be configured at low cost. Further, since the adjustment stage 29b is moved to adjust the light from the objective lens 15 to move to the center of the imaging surface, the aberration generated by the lenses 22 and 23 can be minimized and the adjustment accuracy can be improved. it can. Furthermore, by performing the process of obtaining the tilt angle at which the received light amount is maximized by curve interpolation, the objective lens can be adjusted to the correct posture without sampling the received light amount at all tilt angles. Adjustments can be made.
[0040]
<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention, and further, within the scope not departing from the gist of the invention other than the following. Various modifications can be made.
(1) In the above embodiment, the tilt adjustment is performed in the order of θX and θY. However, for example, the configuration may be such that the tilt adjustment is performed in the reverse order, and both are performed simultaneously. It may be a simple configuration.
[0041]
(2) In the above embodiment, the tilt adjustment of the objective lens 15 is automatically performed under the control of the CPU 27a. For example, a display device such as a monitor is provided, and an image of the beam spot is displayed on the display screen. And the brightness of the central pixel may be displayed, and the operator may adjust the screw of the support member 16 and the adjustment stage 29b. Further, when the adjustment is performed manually, the light from the objective lens 15 can be relatively moved to the center of the imaging surface by moving the optical adjustment device on the XY plane.
[0042]
(3) In the above embodiment, the optical pickup device 1 is placed on the adjustment stage 29b, and the adjustment stage 29b is moved to move the beam spot B to the center with respect to the imaging surface. However, for example, a support mechanism that movably supports the lens optical system and the imaging unit may be provided, and the optical system and the CCD 26 may be moved on the XY plane by moving the support mechanism.
[0043]
(4) In the above embodiment, the lens tilt variable mechanism (support member 16) is provided in the optical pickup device 1 and the tilt of the objective lens 15 is adjusted by controlling the lens tilt variable mechanism. However, the lens tilt angle variable mechanism may be provided outside. As one example, the inclination of the objective lens 15 supported by the support member is adjusted by an adjustment device (lens inclination angle varying mechanism) provided in the optical pickup device 1, and when the adjustment of the inclination is completed, the support member has the inclination. Alternatively, the objective lens 15 may be fixed.
[0044]
(5) In the above embodiment, the CPU 27a performs processing for obtaining a quadratic function by the method of least squares. However, for example, a method of obtaining a quadratic function passing through the sample points from a general expression of a quadratic function is used. May be.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing the configuration of an objective lens tilt adjusting apparatus according to a first embodiment.
FIG. 2 is a flowchart showing main processing of a CPU.
FIG. 3 is a flowchart of an inclination adjustment routine in the θX direction.
FIG. 4 is a flowchart of an inclination adjustment routine in the θY direction.
FIG. 5 is a flowchart of a received light amount acquisition routine.
FIG. 6 is a flowchart of a curve interpolation routine.
FIG. 7 is a schematic diagram of a beam spot irradiated on an imaging surface.
FIG. 8 is a graph depicting sample points of received light quantity for each inclination angle and quadratic curves obtained from these sample points.
FIG. 9 is a graph showing the relationship between the amount of light received on the imaging surface and the coma aberration with respect to the tilt angle of the objective lens.
FIG. 10 is a schematic diagram showing the configuration of a conventional objective lens tilt adjustment device;
FIG. 11 is a schematic diagram of a beam spot formed on an imaging surface.
[Explanation of symbols]
1. Optical pickup device
2 ... Objective lens tilt adjustment device
15 ... Objective lens
16: Support member
26 ... CCD
27a ... CPU
28 ... Driver driving means
29a ... Stage control means
29b ... Adjustment stage
B ... Beam spot
O ... Origin
R: Maximum luminance point
C ... quadratic curve
θX1, θX2, θX3 ... Inclination in the θX direction
θY1, θY2, θY3… Inclination angle in θY direction

Claims (6)

In an optical pickup device comprising a light source and an objective lens that converges and emits light from the light source to the outside, a method of adjusting the tilt of the objective lens,
The light emitted from the objective lens is incident on an optical adjusting device including a lens optical system and an imaging unit, and a beam spot is formed by irradiating the imaging surface of the imaging unit through the lens optical system. While the optical pickup device or the optical adjustment device is moved so that the maximum luminance point of the lens coincides with the intersection point through which the optical axis of the lens optical system passes, one of the tilt angles that the objective lens can take is one with respect to the optical axis. The amount of light received at the maximum luminance point at the first inclination angle in the direction of the second direction, the second inclination angle in the opposite direction, and the third inclination angle different from the first and second inclination angles is sampled. A quadratic curve is calculated based on the amount of light received at the maximum luminance point, and the amount of light received at the maximum luminance point for each tilt angle of the objective lens is calculated. Objective lens tilt adjusting method of an optical pickup device characterized by the amount of light received is adjusting the objective lens in the tilt angle to be maximized. 2. The objective lens tilt of the optical pickup device according to claim 1, wherein the first tilt angle is a maximum tilt angle in the one direction, and the second tilt angle is a maximum tilt angle in the opposite direction. Adjustment method. In an optical pickup device comprising a light source and an objective lens that converges and emits light from the light source, the objective lens tilt adjustment device of the optical pickup device that adjusts the tilt of the objective lens,
An adjustment stage for fixing the optical pickup device, a lens tilt angle varying mechanism for changing the tilt of the objective lens, and a beam spot on the imaging surface by irradiating light emitted from the objective lens of the pickup device through a lens optical system An imaging means for forming the stage, a stage driving mechanism for moving the adjustment stage so that light at the maximum luminance point of the beam spot coincides with the intersection point through which the optical axis of the lens optical system passes, and the objective lens Of the obtained tilt angles, the maximum brightness point at a first tilt angle in one direction with respect to the optical axis, a second tilt angle in the opposite direction, and a third tilt angle different from the first and second tilt angles. Sampling means for sampling the amount of received light, and a secondary curve based on the amount of received light at the maximum luminance point at the first, second and third tilt angles. And calculating means for calculating the amount of light received at the maximum luminance point for each inclination angle of the objective lens, and adjusting the lens inclination variable mechanism so that the amount of light received at the maximum luminance point is maximized. An objective lens tilt adjusting device for an optical pickup device comprising a driving means. 4. The objective lens tilt of the optical pickup device according to claim 3, wherein the first tilt angle is a maximum tilt angle in the one direction, and the second tilt angle is a maximum tilt angle in the opposite direction. Adjustment device. In an optical pickup device comprising a light source and an objective lens that converges and emits light from the light source to the outside, a method of adjusting the tilt of the objective lens,
The light emitted from the objective lens is incident on an optical adjusting device including a lens optical system and an imaging unit, and a beam spot is formed by irradiating the imaging surface of the imaging unit through the lens optical system. While the optical pickup device or the optical adjustment device is moved so that the maximum luminance point of the lens coincides with the intersection point through which the optical axis of the lens optical system passes, one of the tilt angles that the objective lens can take is one with respect to the optical axis. The amount of light received at the maximum luminance point at the first inclination angle in the direction of the second direction, the second inclination angle in the opposite direction, and the third inclination angle different from the first and second inclination angles is sampled. A quadratic curve is calculated based on the amount of light received at the maximum luminance point, and the amount of light received at the maximum luminance point for each tilt angle of the objective lens is calculated. Method of manufacturing an optical pickup apparatus in which the light receiving amount is characterized in that it comprises a step of adjusting the objective lens in the inclination angle is maximum. 6. The method of manufacturing an optical pickup device according to claim 5, wherein the first inclination angle is a maximum inclination angle in the one direction, and the second inclination angle is a maximum inclination angle in the opposite direction.

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