KR20060051918A - Evaluation apparatus of optical system - Google Patents

Abstract

The present invention provides an apparatus for evaluating an optical system that has reduced sensitivity to vibrations.

To this end, in the present invention, the optical axis evaluation device A of the optical system 1 always displays the indicator 8 having the display area and the image projected on the reference plane from the optical system 1 at a reference position on the display area. The projection image capture device 3 is provided. The projection image capture device 3 includes an optical detector 5 for picking up an image projected from the optical system onto a reference plane, and a capture controller 7 for displaying the picked up image at a reference position on the display area. In addition, the capture controller 7 receives a low magnification image and identifies the projection image on the first detection area as a positioning unit 70 for positioning the optical system 1 relatively adjustable with respect to the optical detector 5. The positioning unit 70, which operates to be positioned within the area, receives a high magnification image and displays the projected image at a reference position of the display area of the display device 8, thereby preventing the shake on the display area of the projected image. A projection image shake suppression unit 72 is provided.

Description

Evaluation device of optical system {EVALUATION APPARATUS OF OPTICAL SYSTEM}

1 is a block diagram showing an optical system evaluation device according to an embodiment of the present invention;

FIG. 2 is a front view schematically showing a part of an optical axis adjusting device of an optical pickup for CD or DVD, which is an embodiment to which the optical system evaluation apparatus of FIG. 1 is applied;

3 is a side view showing the mechanism part of the optical axis adjusting device of FIG.

4 is a schematic view showing an optical system of the optical detection unit and the adjusted pickup shown in FIGS. 2 and 3;

5 is a diagram showing a relationship between a detection area of a low magnification CCD camera and a high magnification CCD camera;

6 is a block diagram showing details of an electrical processor of the optical axis adjusting device of FIG. 2;

7 is a block diagram showing details of an X / Y positional information generating circuit of FIG. 4;

8 is a view showing the entire flow of evaluation and adjustment of an optical pickup using the optical axis adjusting device;

FIG. 9 is a flowchart showing the tilt adjustment process of FIG. 8 in more detail;

FIG. 10 is a flowchart showing the remainder of the tilt adjustment process of FIG. 8;

Fig. 11 is a diagram showing low and high magnification beam spot images by a CCD camera;

12 is a diagram showing an actual display example of the luminance profiles of the X and Y axes;

FIG. 13 is a flowchart showing a high speed vibration control flow for suppressing vibration of the beam spot image executed in step S32 of FIG.

※ Explanation of code for main part of drawing

DESCRIPTION OF SYMBOLS 1: Optical system under evaluation 3: Projection image capture

5 optical detector 7 capture controller

8 indicator

TECHNICAL FIELD The present invention relates to an evaluation apparatus or an adjusting apparatus of an optical system such as an optical pickup for a CD or a DVD, and particularly to an evaluation or adjustment of the seismic structure and the tilt of an optical axis of such an apparatus.

Conventionally, the optical axis evaluation device or the adjustment device of the optical system of the optical pickup for CD or DVD has adjusted the tilt of the optical axis of the objective lens of the pickup by enlarging and displaying a beam spot image generated by the beam from the pickup. Such a conventional optical axis evaluation / adjustment device is designed to be used in a state where the vibration from the external environment with respect to the evaluation / adjustment device is suppressed to a certain limit or more because of the high magnification of the spot image. Therefore, in order to use such an optical axis evaluation / adjustment apparatus, it is necessary to take sufficient anti-vibration measures, such as providing an evaluation / adjustment apparatus on a dustproof stand.

However, the dustproof belt is generally expensive, and further, as the dustproof performance is increased, it becomes more expensive. This raises the price of the entire installation including the optical axis evaluation / adjustment device. In addition, such a conventional optical axis evaluation / adjustment device is that the device itself is sensitive to vibrations from the outside, and the influence of vibration caused by the operation of manually adjusting the inclination of the objective lens when the inclination of the objective lens of the optical pickup is adjusted. Also greatly receives. Such sensitivity to vibration also causes a problem that the adjustment work must be temporarily stopped until the vibration is rectified. There is also a vibration caused by the movement of another part of the optical axis evaluation / adjustment device, for example, an X / Y stage for position tracking (tracking of a beam spot image). Such vibration also makes the time required for adjustment work long.

It is therefore an object of the present invention to provide an evaluation device or an adjusting device for an optical system that has reduced sensitivity to vibrations.

It is an object of the present invention to provide an apparatus for evaluating or adjusting an optical axis of an optical system that has reduced sensitivity to vibrations.

According to one embodiment of the present invention, an optical system evaluating apparatus provided by the present invention includes a stage, a base supported on the stage, and an X / Y stage mounted on one side of the base above and below the base. And an optical detector mounted on the other side above and below the base for mounting the optical system device. The optical system evaluating apparatus may include image processing means, and the image processing means processes the image from the optical detector that detects the projection image from the optical system apparatus to be evaluated, thereby projecting the image in the image. Suppress the shaking of the.

According to another aspect of the present invention, an optical axis evaluation apparatus for an optical system provided by the present invention includes: a display having a display area and a projection image which always displays an image projected on a reference plane from the optical system at a reference position on the display area. Means. The projection image capturing means may include an optical detector for capturing an image projected from the optical system onto the reference plane, and a capture controller for displaying the captured image at a reference position on the display area. The optical detector detects a pseudo disc constituting the reference plane that receives the image projected by the optical system on the optical axis, and a first detection that generates a first captured image by imaging the projection image on the reference plane at a first magnification. A second detector having a first detector having an area and a second detection area for imaging the projected image at a second magnification higher than a first magnification to generate a second captured image, wherein the second detection area is the first detector; The above-described second detector corresponding to a specific area in the detection area may be provided. The capture controller is positioning means for receiving the first picked-up image and positioning the optical system relatively adjustable relative to the optical detector, the capture controller being operable to be positioned within a specific area within the first detection area. The projection image which receives the said positioning means and the said 2nd picked-up image, and displays the image of the said projection image in the reference position of the said display area of the said display, and suppresses the shake in the said display area of the projection image. Shake suppression means may be provided. The projection image shake suppression means generates an image portion including projection image position detecting means for detecting a position of the projected image in the second captured image, and the projected image position in the second captured image, An image extracting means for supplying the display device may be provided. The projection image position detecting means corresponds to the center of the projection image from a memory having a plurality of addresses arranged in a matrix for storing data of the second captured image, the plurality of addresses, and image data stored at these addresses. As the center calculating means for calculating the center address, the center calculating means may be provided in which the center of the projection image indicates the position of the projection image.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described in detail with reference to drawings.

1 shows an optical system evaluation device A according to one embodiment of the present invention. As shown, this optical system evaluating apparatus A evaluates the optical parameters (for example, the inclination of the optical axis) of the optical system to be evaluated, that is, the optical element (for example, the objective lens) in the adjusted optical system 1. In order to achieve this, the projection image capture device 3 is provided. The projection image capturing apparatus 3 includes an optical detector 5 for capturing a projected image from the optical system 1 to be adjusted, for example, a beam spot (BS) image by a beam passing through an optical element in the optical system. A capture controller 7 is provided. The optical system evaluating device A also includes a display 8 for displaying the captured projection image at a reference position on the display area.

In detail, the optical detector 5 is provided with the reference surface which receives the projection image from an optical system, and is equipped with the 1st detector 50 and the 2nd detector 52 which image the projection image on this reference surface. The first detector 50 has a first two-dimensional detection region, and captures the projection image on the reference plane at a low magnification to generate a low magnification image, and the second detector 52 is a second two. It has a dimension detection area, and the projection image is picked up at high magnification to generate a high magnification picked-up image. Here, the second detection region of the second detector 52 corresponds to the target region which is a small region of the center portion in the first detection region of the first detector 50. In addition, the capture controller 7 includes a positioning unit 70 and a projection image shake suppression unit 72. The positioning unit 70 positions the adjustable optical system 1 to be adjustable relative to the optical detector 5 so that the projection image is located in the target area on the first detection area. ) And a position adjusting unit 702. Therefore, the positioning unit 70 puts the projection image into the target area when the projection image is outside the target area, and operates to stay within the target area when trying to exit this area while in the target area. It also allows the movement of the projection within the target area.

In addition, the projection image shake suppression unit 72 receives the high magnification picked-up image from the second detector 52 and displays the projected image at the reference position of the display area of the display device 8 to thereby display the projected image on the projected image. The projection image position detecting unit 720 and the image extracting unit 722 are provided to suppress the shaking in the apparatus. As described above, since the positioning unit 70 permits the movement of the projection image in the target area, in the high magnification imaging image of the projection image, the projection image is greatly shaken due to the vibration applied to the optical evaluation device A. see. For this reason, the projection image position detection part 720 detects the position of the projection image in the high magnification picked-up image from the 2nd detector 52, and the image extracting part 722 is the projection image position in a high magnification picked-up image. Generates an image portion including a and supplies it to the display device 8. The display device displays the image portion from the image extracting section 722 at the reference position of the display area, thereby suppressing the shaking on the display area of the projection image. This actually stopped projection image makes it possible to easily perform a predetermined kind of adjustment of the optical element of the to-be-adjusted optical system 1 (for example, the inclination of the optical axis).

Next, the optical axis adjusting device B of the optical pickup for CD or DVD, which is an embodiment to which the optical system evaluating apparatus A of FIG. 1 is applied, will be described with reference to FIGS. This optical axis adjustment device B is used to adjust the inclination of the optical axis of the objective lens provided in the optical pickup.

First, the mechanism part of the optical axis adjustment device B is demonstrated in detail with reference to FIGS. In addition, the element corresponding to the element of Fig. 1 is denoted by the symbol “B”. Fig. 2 shows a schematic front view of the mechanism part of the optical axis adjusting device B, and other electrical processing parts. It is a side view which shows the partial cross section of the mechanism part of FIG. 2, and FIG.4 is a schematic diagram which shows the optical detection unit shown in FIG.2 and FIG.3 and the optical pickup of adjustment object. The mechanism part of the head) is comprised by the support mechanism 2B which can install the to-be-adjusted pickup 1B, and the optical detection unit 5B provided in this support mechanism 2B, and the electrical processing part of the optical axis adjustment device B The preamplifier unit 7B-1 provided in the support mechanism 2B, the computer main body portion 7B-2 provided separately from the support mechanism 2B, the display portion 8B, and the remote control portion 9B. It consists of).

More detailed description of the mechanism portion, as can be seen in Figures 2 and 3, the support mechanism 2B is a support plate 200 which is a horizontally mounted plate, and two side plates 202 provided in the support 200. And 204, a back plate 206, and a common base 208 supported by these plates. These stages, side plates, and the base are firmly fixed to each other by screws or the like. Moreover, the mechanism part is equipped with the optical detection unit 5B provided in the upper surface of the base 208, and the X / Y stage 220 provided in the lower surface of the base 208. As shown in FIG. The optical detection unit 5B has a main body portion 50 and a mirror barrel portion 55 extending downward from the main body portion 50. The X / Y stage 220 includes an X-axis stage 222 having a fixed portion mounted on the bottom surface of the base 208 and a Y-axis stage 224 having a fixed portion mounted on the bottom surface of the movable portion of the X-axis stage 222. And a pickup mounting head 226 attached to the lower surface of the movable portion of the Y-axis stage 224. The installation head 226 has an installation mechanism for installing the adjusted pickup 1B, and the installation mechanism includes two horizontally arranged shafts (main shaft and subshaft) 225 mounted to the installation head, Springs (not shown) for fixing the pickups inserted into these shafts are provided. In addition, the X / Y stage 220 includes X- and Y-axis stepping motors 228 and 229 (only one shown in FIG. 3) provided on the rear surface of the back plate 206, whereby the X-axis stage ( Each of 222 and Y-axis stage 224 is driven. The stepping motors 228 and 229 control the amount of movement of the X / Y stage via a circular cam 227 (shown above the stepping motor in FIG. 3) shifted from the center axis by the rotational position of the stepping motor (i.e., The stage is moved by pressing the plate 221 provided on the X / Y stage with a cam]. Moreover, as for the support mechanism 2B, the installation head 226 is provided with the mechanism (not shown) which rotatably supports the pair of inclination adjustment knobs 230. As shown in FIG. As a result, each of the inclination adjustment knobs is a driver at the tip, so that two screws for determining the inclination of the objective lens of the adjusted pickup 1B can be turned correspondingly.

As described above, since the optical detection unit 5B and the X / Y stage 220 are mounted on a common base 208 with each other, the optical detection unit 5B and the optical detection unit 5B The relative positional relationship between the pick-up pickup 1B provided therein along the X / Y stage 220 is a structure with little change in at least the horizontal direction. In addition, since the optical detection unit 5B and the X / Y stage 220 are disposed on opposite sides of the top and bottom surfaces of the base 208, the base 208 can be a common support point, so that the relative change in positional relationship is achieved. Can be further reduced (the change in the relative relationship between the optical detection unit 5B and the X / Y stage 220 with respect to external vibration is small). In addition, since the optical detection unit 5B and the X / Y stage 220 are closely aligned in the vertical direction by mounting on a common base, the change in relative positional relationship in the vertical direction is also reduced.

Referring next to FIG. 4, this schematically shows the optical system of the optical detection unit 5B and the adjusted pickup 1B. First, the adjusted pickup 1B includes a base portion 10 and an objective lens support 12. As shown schematically, the base portion 10 includes a main body 100, and includes a laser diode 102, a collimator lens 104, and a mirror 106 in the main body 100 to generate a laser. The laser beam from the diode 102 is turned upward. The objective lens support 12 includes a main body 120 and a focus actuator 122 mounted in the main body, and the focus actuator 122 is mounted to move the objective lens 124 in the vertical direction. . The objective lens 124 receives the beam from the laser diode 102 via the mirror 106 to focus at the position of the focal length above. This position is adjustable with the focus actuator 122. The objective lens support 12 is provided so as to be adjustable with two screws 126 and 128 with respect to the base portion 10. These two screws, that is, the inclination angle adjustment screw, can be used for adjustment of the inclination in the X-axis direction and the Y-axis direction, as is well known in the art.

The optical detection unit 5B has a main body 50 and a mirror cylinder 55 as described above, but the mirror cylinder 55 includes a cylinder 550 and a similar disk 552 provided at the front end thereof. And an objective lens 554 provided in the barrel 550. The back surface of the pseudo disk 552 is the focal plane 556. The focal plane 556 constitutes a reference plane on which the beam spot from the objective lens of the adjusted pickup 1B is projected, and the beam spot BS image on the focal plane is the objective lens 554. Is converted into parallel light. In addition, the main body 50 of the optical detection unit 5B includes a low magnification CCD camera 500 and a high magnification CCD camera 520 to detect beam spot images on the focal plane 556, and also includes a focus detection sensor. 560 is also provided. The low magnification CCD camera 500 is a two-dimensional imaging device that receives a beam spot image from the objective lens 554 via the half mirror 502 and through the focusing lens 504. The focus detection sensor 560 receives the beam spot image from the half mirror 502 through the half mirror 562 and through the focusing lens 564. In addition, the high magnification CCD camera 520 passes the beam spot image from the half mirror 502 through the half meter 562 and the mirror 522 and through the focusing lens 524. .

Here, the relationship between the detection area of the low magnification CCD camera 500 and the high magnification CCD camera 520 will be described with reference to FIG. 5. As shown, the imaging area of the low magnification CCD camera 500 is detection area SA1 (FIG. 5 (a)), and this detection area SA1 has the target area TA which is a small area in the center part. It is located. On the other hand, the imaging area of the high magnification CCD camera 520 constitutes the detection area SA2 (Fig. 5 (b)), which corresponds to the small target area TA in the detection area SA1. In addition, the magnification ratio of the low magnification CCD and the high magnification CCD is 20 times, for example. As described above, when the beam spot BS image P enters the detection area SA1, the optical axis adjusting device B enters the target area TA as indicated by "P '". The position of the X / Y stage is controlled, whereby in the high magnification detection area SA2, for example, it appears at a position shifted from the center to the lower left. In addition, the position of the BS image in the detection area SA2 is greatly shaken by the vibration received by the optical axis adjusting device B. In the optical axis adjusting device B of the present invention, an image portion having a constant size including the BS image P 'in the detection area SA2 is cut out. The image portion of the cropping area CA is displayed on the display area DA (Fig. 5 (c)) of the display device 8B, so that the image BS 'is stopped in the display area DA. In addition, the focus detection sensor 560 has a two-dimensional detection area similarly to the conventional focus sensor, and detects whether or not the focus state is in focus by using a conventional method such as astigmatism. In addition, the focus detection sensor 560 can use any conventional type that can detect the focus state as long as the beam spot BS image is within the target area TA. Omit.

Next, with reference to FIG. 6, the electrical processing part of the optical axis adjustment device B is demonstrated in detail. Fig. 6 shows an optical detection unit 5B (including a low magnification CCD camera 500, a high magnification CCD camera 520 and a focus detection sensor 560) included in the above mechanism part, the adjusted pickup 1B and X / In addition to the Y stage 220, the preamplifier unit 7B-1, the computer main body portion 7B-2, the display portion 8B and the remote control portion 9B are shown in more detail. As shown, the preamplifier unit 7B-1 includes a local CPU 7000, an X / Y position information generating circuit 7002, a stepping motor driver 7020, and an auto power control (APC) circuit 7040. ), A focus servo circuit 7042, and a power supply 7042. In detail, the local CPU 7000 is programmed to control the focus adjustment in the optical axis adjusting device B and the position adjustment of the X / Y stage, and is provided with various inputs and outputs. That is, the local CPU receives, from the remote control unit 9B, an LD-ON signal instructing the lighting of the laser diode in the optical pickup, a focus ON signal indicating the start of focus adjustment, and other remote control signals. Further, the local CPU uses a set of X / Ys used for detecting the position of the beam spot BS image (shown in FIG. 5) in the detection area SA1 from the X / Y position information generation circuit 7002. A position detection signal is received, and a home position signal output indicating the home position of the stepping motor 228/229 is received. In addition, the local CPU generates a lighting signal to the output in response to the LD-ON signal and supplies it to the APC circuit 7040. In addition, the local CPU generates a triangular wave voltage at the output in response to the focus ON signal and supplies it to the focus servo circuit 7042, and in response to the position detection signal from the X / Y position information generation circuit, the X / Y position. And output the position control signal of the X / Y stage according to the detected X / Y position to the output and supply it to the stepping motor driver 70,20. Further, the local CPU generates a focus servo ON signal to the output when the beam spot BS image is in the target area TA in the detection area SA1 and supplies it to the focus servo circuit 7042. In addition, when the signal indicating the focus state ON indicating the focusing state of the objective lens 124 is generated, the local CPU issues a tilt measurement start signal to the output and supplies it to the computer main body 7B-2.

In more detail, when the APC circuit 7040 receives the lighting signal from the local CPU, the APC circuit 7040 applies a voltage to a terminal for controlling the output power of the laser diode 102 (FIG. 4) of the adjusted pickup 1B. It turns on and detects the output of the monitor diode (this is a diode for monitoring the amount of light of the laser diode 102 of the pickup, not shown in FIG. 4) and controls the voltage applied so that the value becomes a prescribed value. This projects the beam spot BS image onto the focal plane 556 of the pseudo disk. The X / Y positional information generating circuit 7002 is connected to the low magnification CCD camera 500 to receive the video signal output from this CCD, and to output the detection area SA1 of the BS image P (shown in FIG. 5). The BS image position detection signal used for the detection of the position in the parentheses) is generated at the output and supplied to the local CPU. The driver 7020 drives the stepping motor 228 (Fig. 3) in response to the position control signal received from the local CPU.

In addition, the focus servo circuit 7042 provided in the preamplifier unit 7B-1 has an input connected to the focus detection sensor 560 to receive a signal indicating the focus state from the sensor, and one at the output. In the operation mode, i.e., the position detection mode, receives a triangular wave voltage from the local CPU to generate a triangular wave output, and in another operation mode, the focus servo mode, generates a focus adjustment signal according to the detected focus state. . The position detection mode is entered when the focus ON signal is received from the local CPU, and the focus servo mode is entered when the focus servo ON signal is received from the local CPU. In any case, the triangular wave output or the focus adjustment signal is supplied to the focus actuator 122 of the adjusted pickup 1B, and this actuator moves or moves the position of the objective lens 124 along the optical axis direction. In the focus servo mode, the focusing state of the objective lens 124 is maintained, and when the focus servo circuit 7042 detects this focusing state, a focus state ON signal indicating this is generated at the output and supplied to the local CPU. do. The power supply 7044 included in the preamplifier unit 7B-1 is connected to supply power to the CCDs 500 and 520 and the adjusted pickup 1B. In addition, the preamplifier unit 7B-1 includes a CCD output conversion switch SW, which selects one of the outputs of the low magnification CCD 500 or the high magnification CCD 520 to the computer main body 7B-2. Supply. Normally, this switch SW is set to select the output of the high magnification CCD 520. The output of each CCD is also connected to each monitor output terminal for monitoring of each CCD camera output.

In addition, as shown in FIG. 6, the computer main body 7B-2 includes a video A / D board 7200 that receives video signal output from the preamplifier unit 7B-1. The video signal converted into the digital state of the signal is processed to generate an image for adjusting the tilt of the objective lens, and the image signal is supplied to the display monitor of the display portion 8B. Although the position control in the positioning unit 70 in FIG. 1 is realized in the preamplifier unit 7B-1, the function of the projection image shake suppression unit 72 in FIG. 1 is the computer main unit 7B-. It is realized by the program executed in 2).

Here, with reference to FIG. 7, the detail of one Embodiment of the X / Y positional information generation circuit 7002 is demonstrated. The X / Y position information generation circuit 7002 includes a synchronous separation circuit 70020, a pedestal clamp circuit 70022, and a binarization circuit 70024 that receive a video signal from the low magnification CCD camera 500 as shown. Equipped with. In detail, the sync separation circuit 70020 generates a vertical sync signal and a horizontal sync signal, an even / odd field discrimination signal, and a back-poch clamp signal from the received video signal. When the vertical synchronization signal becomes high (H) after a predetermined time from the start of one vertical period, the horizontal synchronization signal becomes high at the start of one horizontal period, and the even / odd field discrimination signal is an odd field. It becomes low (L) when it is a high or even field. The synchronous separation circuit for generating such a signal is well known and can be realized by, for example, a commercially available video synchronous separation IC. The clamp circuit 70022 also has an input for receiving a video signal from the CCD camera 500, an input for receiving a back-porch clamp signal from the synchronous separation circuit, and a period of the back-porch clamp signal. The video signal is clamped so that the direct current level of the video signal becomes the ground level. The binarization circuit 70024 having an input for receiving the clamped video signal generates a binarized signal that is at a high level when it is above a predetermined threshold and is at a low level when it is below it. Here, the predetermined threshold is for detecting the beam spot (BS) image.

The vertical synchronizing signal, the horizontal synchronizing signal, the even / odd field discrimination signal, and the binarization signal constitute a set of X / Y position detection signals used for detecting the position of the beam spot image described above, and It is input to the local CPU.

The counter 1 in the local CPU starts counting the number of horizontal synchronizing signals following the vertical synchronizing signal when the field discrimination signal is high indicating an odd number, and when the binarization signal becomes high between the fields. Stop counting. The count value at the time of this stop becomes a Y-axis position count and shows the position of the beam spot BS image P in the detection area SA1 in the Y-axis direction. For example, when the count value of the counter 1 is smaller than the predetermined value A (for example, 127), the image BS is located above the center of the screen, and when larger than the value, the image BS is positioned below the screen. . The position in the Y-axis direction of the image BS is calculated according to the difference from the predetermined value A. FIG. On the other hand, the counter 2 in the local CPU starts counting when the horizontal synchronizing signal becomes high, and reaches a predetermined value B (for example, 62.0 microseconds) corresponding to one horizontal period. For example, the time is measured by counting the reference clock, and when the binarized signal becomes high within one horizontal period, the count is stopped at that time. The count value at this time becomes an X-axis position count and shows the X-axis position in the detection area SA1 of BS image P. FIG. However, if the binarized signal does not become high in one horizontal period, the count 2 is erased, and then the count for one horizontal period is started. For example, when the measurement time is smaller than the predetermined value B, the image BS determines that it is to the left of the screen center and to the right of the screen center if it is larger than the predetermined value B. As can be seen from the above, the X / Y position is detected during the period of the odd field. In the even field period, the X / Y stage is controlled so that the image B S is at the center of the screen according to the X / Y position detected during the odd field period. The counters 1 and 2 described above are implemented in software, but may also be configured in hardware.

Next, the entire flow of evaluation and adjustment of the optical pickup using the optical axis adjusting device B described with reference to FIGS. 2 to 7 will be described with reference to FIG. 8. First, in step S2, the optical pickup to be adjusted is mounted by inserting a pickup into the two shafts 225 provided on the mounting head 226 of the optical axis adjusting device B and fixing them with spring pressure. Next, when the LD-ON switch in the remote control unit 9B is operated in step S4, in response to the LD-ON signal from this switch, the local CPU 7000 supplies a lighting signal to the APC circuit 7040 to avoid the operation. The laser diode 102 of the adjustment pickup 1B is turned on. As a result, the beam spot BS image is projected onto the focal plane 556 of the pseudo disk. Next, the tilt of the objective lens 124 is adjusted in step S6. This inclination adjustment process includes a capture / tracking step of the BS image used for focus adjustment, a focus adjustment step subsequent to this, and further includes a vibration suppression step of the BS image and an inclination adjustment operation by the operator. In the adjustment operation, the operator performs the inclination of the objective lens of the optical pickup by turning the adjustment screws 126 and 128 with the inclination adjustment knob based on the vibration suppressed BS image. When this step is completed, the optical axis adjustment work of the optical pickup ends.

Next, referring to FIGS. 9 and 10, the inclination adjustment process S6 of FIG. 8 will be described in more detail. This adjustment process includes capturing / tracking the BS image as described above. First, in step S10, in response to the operation of the focus ON switch of the remote control unit, the local CPU 7000 sends a focus ON signal to the focus circuit 7042. FIG. Next, in step S12, the focus servo circuit enters the position detection mode and applies a triangular wave to the focus actuator 122 of the pickup to find the objective lens position to which the BS image is focused. That is, since the BS spot image is not observed in the CCD camera 500 unless the light from the adjusted pickup is focused near the focal plane of the pseudo disk, the focus actuator is moved up and down to find the approximate focusing position. It works. As a result, the objective lens 124 vibrates in the optical axis direction (up and down direction in Fig. 4), thereby changing the focus state on the focal plane 556 of the similar disk of the BS image. It is assumed that the BS image P is at least in the detection area SA1 of the CCD camera 500. In the meantime, in step S14, the local CPU detects a signal from the X / Y positional information generating circuit 7002. That is, when the focus actuator is near the focused state, the local CPU receives the Y-axis position count and the X-axis position counter from the counter 1 and the counter 2 in FIG. Detect the Y position. In step S16, when those counts are received, i.e., the position of the objective lens near the focusing state is known, the change range of the amplitude of the triangle wave is reduced centering on the voltage value of the triangle wave when the count is received. As a result, a focused state of the BS image or a near focus state is always obtained. Next, in step S18, the local CPU compares the magnitude of the BS image position indicated by the Y-axis position count and the X-axis position count within the target area TA with the coordinates that define the boundary of the target area TA. By doing so. When judged to be outside the target area, the error amount between the image position and the boundary is calculated, and the position control signal is supplied to the stepping motor driver to move the X / Y stage in the direction of decreasing the error amount. Next, in step S20, it is determined whether or not the position of the BS image is in the target area TA, and in the case of NO, step S18 is repeatedly executed, and in the case of YES, the flow goes to step S22.

FIG. 11A shows an actual CCD camera image in a state where the BS image is in the target area TA of FIG. 5A. As can be seen from the image of Fig. 11 (a), the beam spot image is located at the center of the area. In addition to the central image, two small beams are also visible, but these are sub-beams and have no direct relationship with the present invention.

In addition, in step S22 in FIG. 9, since the BS image is in the target area TA, the local CPU generates a focus servo ON signal to the focus servo circuit 7042. As a result, the focus servo circuit 7042 enters the focus servo mode, and operates the focus servo in this mode. In this focus servo mode, the focus servo circuit 7042 stops the application of the triangle wave and supplies a signal to the focus actuator 122 to return to the focusing state only when the triangle wave is shifted from the focusing state. The focus is always maintained even during the tilt adjustment of. This focusing state is maintained from the focus servo circuit 7042 to the local CPU by the focus state ON signal. In step S24, when the local CPU detects the focus state ON signal from the focus servo circuit, in step S26, a tilt measurement start signal is generated and supplied to the computer main body 7B-2.

Next, with reference to FIG. 10, the remaining part of the inclination adjustment flow of FIG. 8 is demonstrated in more detail. First, when the personal computer of the computer main body 7B-2 receives the inclination measurement start signal from the local CPU 7000 in step S30, the video signal from the high magnification CCD camera 520 is transferred to the video A / D board (step S32). 7200 converts to a digital signal, and detects the center position of the BS image in the detection area SA2 (Fig. 5 (b)) from this digital signal, and then again the area centered on the detected center position, i.e. The vibration in the beam spot image is suppressed by cutting out the image in the cropping area CA and displaying it on the display monitor 8B. Fig. 11B shows the BS image in the cropping area from the actual high magnification CCD camera image. Next, in step S34, the profile of the luminance along the X axis and the Y axis passing through the center of the BS image is also displayed at the same time.

12 shows an actual display example of the luminance profiles of the X and Y axes. As can be seen from the figure, it can be seen that there is a substantially circular phase in the center and a primary ring which is the other first ring-shaped phase.

Next, in step S36 of FIG. 10, the luminance difference of the primary ring is calculated from the monitor screen of the image of the cropping area CA, and how much luminance difference is in which direction is shown in another region (not shown) on the monitor. In format. Next, in step S38, when the length of the vector, that is, the luminance difference is within a certain threshold, the slope displays "OK" within the allowable range, and when it exceeds the threshold, "NG" is displayed. When this is finished, the process returns to step S32 again, and the above steps are repeatedly executed during the tilt adjustment.

Next, with reference to FIG. 13, the high-speed vibration control flow which suppresses the vibration of the beam spot image performed in step S32 of FIG. 10 is demonstrated in detail. First, in step S40, the personal computer 7B-2 introduces an odd field of pixels constituting the video signal from the high magnification CCD into the memory (pixel data for one field is introduced at a time). In the next step S42, the luminance signal is read in sequence from the first address of the memory that stores pixel data for one field (only luminance signal components in the case of black and white) which are odd fields. In the next step S44, the memory address of the pixel data whose luminance is equal to or greater than a threshold value (to determine the presence or absence of the beam spot image) is stored. When the luminance determination with respect to the odd field of pixel data is completed, in step S46, the center of the beam spot image is calculated from the plurality of memory addresses stored in step S44.

Generally, such center calculation can be performed by the following formula, considering the luminance of each pixel data as a mass.

Where M is the center address, m is the luminance of the pixel data, x is the memory address of the pixel data, and n is the total number of addresses of one field of memory. The denominator in this equation is the sum of the memory address value and the pixel data product, and the numerator is the sum of the pixel data.

In the present invention, the above calculation is simplified. That is, in step S44, the pixel data is binarized using a threshold value to be " 0 " and " 1 ". Accordingly, in the calculation of the numerator, the term of m _i x _i by the pixel data below the threshold can be excluded in advance, and the term m _i x _i used in the calculation is m = 1 by binarization. For this reason, only the value of the memory address having the luminance equal to or higher than the threshold is obtained. The denominator can be calculated by the total number of pixel data having a threshold value or more, that is, the number of memory addresses having data of "1" by binarization. Therefore, M is the sum of the memory address values stored in step S44 divided by the number of memory addresses stored in step S44. In the present invention, since the calculation amount decreases, the calculation of the center can be performed at high speed. However, as long as a speed sufficient for the inclination adjustment can be realized, the above equation (1) may be used as it is. In the present embodiment, the pixel data for one field is stored in the memory, and then the data is read from the memory and the center calculation is performed. However, the above calculation can be performed in parallel with writing to the memory.

The center calculated as described above is used in the monitor display positioning function in step S48 to suppress vibration of the beam spot image. Here, the monitor display position designation function means that if an address of the center position of the image P on the screen of the detection area SA2 is designated, the predetermined range including this position, that is, the cropping area in Fig. 5B. It is a function to display the image portion of (CA) on the monitor. This function determines, from the pixel data stored in the video memory having the address space, a cutting address space corresponding to the cutting area CA including the center address, and iteratively repeats the pixel data from this cutting address space. Read and supply to monitor. As an example, the monitor display positioning function uses commercial software "VisualBasic", whereby (1) a display area is specified, and (2) a data file in memory (area SA2) displayed by a picture load command. Corresponding data] and (3) designating coordinates (memory address) corresponding to the starting point of the cutting area CA in the data file specified in (2) by the comments of the top and the left. This can be achieved. As a result, the beam spot image is stopped and shown as shown in FIGS. 5C and 12. The operator who is adjusting the tilt can be performed while viewing the spot image at which the tilt screw is stopped.

The apparatus for adjusting the inclination of the optical axis according to the embodiment of the present invention described above can be used for adjusting the inclination of the objective lens or for adjusting the inclination of the optical axis of other lenses or optical systems as will be understood by those skilled in the art. In the above embodiment, the positioning unit 70 and the projection image shake suppression unit 72 are realized by a combination of software and hardware. However, depending on the processing speed of the CPU which is realized by all hardware or used in some cases, It can be realized with any software.

According to the present invention, it is possible to make the dustproof stand as used conventionally unnecessary, or to use a simpler dustproof stand. Moreover, the cost of the whole evaluation apparatus or adjustment apparatus of an optical system can also be reduced by this. In addition, in the present invention, the tilt of the optical axis can be adjusted even under a vibration larger than conventionally. This also eliminates the need for a high position tracking capability by the X / Y stage as in the prior art, thereby simplifying and reducing the position tracking.

Claims (19)

As the evaluation device of the optical system, Wow, The base supported on the table, An X / Y stage mounted on one of the upper side and the lower side of the base, wherein the X / Y stage for mounting the optical system device to be evaluated on the stage; And an optical detector mounted on the other side of the base and the other side of the base. The method of claim 1, Further comprising image processing means, And the image processing means suppresses the shaking of the projection image in the image by processing the image from the optical detector that detects the projection image from the optical system apparatus of the evaluation object. The method of claim 2, Further provided with an indicator, The indicator has a display area for displaying the image from the image processing means, And the projection image in the image displayed in the display area is displayed at a reference position in the display area. The method of claim 1, The base and the base extend in a horizontal direction, The X / Y stage, the optical system evaluation apparatus, characterized in that to move the optical system device of the evaluation target relatively in the horizontal direction relative to the base. The method of claim 4, wherein The X / Y stage includes an installation head for installing the optical system device of the evaluation target, The mounting head, the optical system evaluation apparatus, characterized in that the optical axis of the optical system included in the optical system device is installed so as to generally face in the vertical direction. The method of claim 5, The optical detector includes a detection optical system for receiving an image projected from the optical system device of the evaluation target, The detection optical system of the optical detector extends vertically from the other side of the base on which the optical detector is mounted to the one side on which the X / Y stage is mounted, so that the front end of the detection optical system is on the X / Y stage. The optical system evaluation apparatus, characterized in that positioned in the vicinity of the optical system of the optical system device of the evaluation target. The optical system adjustment apparatus provided with the optical system evaluation apparatus in any one of Claims 1-6. An apparatus for evaluating an optical axis of an optical system, An indicator having a display area, And an projection image capturing means for always displaying an image projected on a reference plane from the optical system at a reference position on the display area. The method of claim 8, The projection image capturing means, An optical detector for capturing an image projected from the optical system onto the reference plane; And a capture controller for displaying the picked-up image at a reference position on the display area. The method of claim 9, The optical detector, A pseudo disk constituting the reference plane that receives the image projected by the optical system on its optical axis; A first detector having a first detection region for imaging the projection image on the reference plane at a first magnification to generate a first captured image; A second detector having a second detection region for imaging the projected image at a second magnification higher than a first magnification to generate a second captured image, wherein the second detection region is located in a specific region within the first detection region. And a corresponding second detector. The method of claim 10, And the first and second detectors comprise a two-dimensional imaging device. The method of claim 11, The two-dimensional image pickup device is an optical system optical axis evaluation device, characterized in that the CCD camera for generating a signal of a video signal format. The method of claim 10, The capture controller, Positioning means for receiving the first captured image and positioning the optical system relatively adjustable with respect to the optical detector, wherein the projected image is operative to be positioned within the specific area on the first detection area Determination means, And a projection image shake suppression means for receiving the second captured image and displaying the image of the projection image at a reference position of the display region of the display to suppress the shaking on the display region of the projection image. Optical system optical axis evaluation apparatus. The method of claim 13, The projection image shake suppression means, Projection image position detection means for detecting a position of the projection image in the second captured image; And an image extracting means for generating an image portion including the projected image position in the second picked-up image and supplying it to the display. The method of claim 14, The projection image position detecting means, A memory having a plurality of addresses arranged in a matrix for storing data of the second captured image; A center calculation means for calculating a center address corresponding to the center of the projection image from the plurality of addresses and the image data stored in these addresses, wherein the center calculation means includes the center calculation means in which the center of the projection image indicates the position of the projection image. Optical system optical axis evaluation device characterized in that. The method of claim 15, The center calculation means, Storage means for storing an address of the luminance signal when the luminance signal of the image data of one field stored in the plurality of addresses of the memory is equal to or greater than a threshold value; Calculating means for calculating the center address by receiving at least one address stored in the storage means for the image data of the one field, adding the value of the at least one address and dividing by the number of the at least one address; Optical system optical axis evaluation device characterized in that provided. The method of claim 15, The image extracting means, An address space means for determining an address space including said center address, said address space means for generating an address of said address space sequentially; And reading means for receiving an address from the address generating means and reading out image data stored in the corresponding address of the memory and supplying the image data to the display. The method of claim 15, The indicator has a monitor display positioning function, The extracting means uses the center address as a monitor display positioning address, Thereby, the shaking of the projection image on the display area of the said indicator is suppressed, The optical system optical-axis evaluation apparatus characterized by the above-mentioned. An optical system optical axis adjusting device comprising the optical system optical axis evaluating device according to any one of claims 8 to 18.

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