JPH0695002A - Light pickup assembling adjusting device - Google Patents

Abstract

PURPOSE:To improve handleability and the reliability of assembling by adding a servo function to the disk surface focusing of a microscope. CONSTITUTION:This device is provided with a reference surface member 25 with light transmissivity, where a reference level difference shape is formed by ruggedness on a reference surface P being the convergent point of a beam condensed by an objective lens 5, an objective lens for a microcope 27 for observing a condensed light spot from a light pickup 21, which is transmitted through the member 25, and the reference level difference shape illuminated by a light source 29 for illumination, a monitor 31 for observing branched beams from the lens 27, a fixing member 26 integrally holding the lens 27 and the member 25, and a reference surface varying mechanism 36 capable of varying a distance between the lens 27 and the member 25 in the optical axis direction of the microscope on the member 26.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical pickup assembling adjusting device which can be applied to a microscope sample stand or the like.

[0002]

2. Description of the Related Art Conventionally, as an assembling adjusting device for an optical pickup using a microscope, for example, Japanese Patent Application Laid-Open No. 2-29494 is known.
In Japanese Patent Laid-Open No. 4 and Japanese Patent Laid-Open No. 3-292634, there is one disclosed under the title of "optical head adjusting device". Therefore, an example of a conventional optical pickup assembly adjustment device will now be described with reference to FIG. The light emitted from the laser light source 1 is collimated by the collimator lens 2, is reflected by the beam splitter 3, is vertically raised by the raising mirror 4, is focused by the objective lens 5, and is condensed by the surface of the half mirror 15. A light spot is illuminated on the top. Then, the light reflected by the half mirror surface becomes parallel light again by the objective lens 5, passes through the polarization beam splitter 5 as it is through the rising mirror 4, and is guided to the detection lens 8 in the signal detection optical system 7. Get burned.
The focused light transmitted through the detection lens 8 is divided into two (transmitted or reflected) by the beam splitter 9. Of the two split lights, the reflected light is given astigmatism by the cylinder lens 10 and is received by the four-split light receiving element 11. The output signal obtained by this light reception is passed through the control mechanism 12 to the objective. By being sent to the lens actuator 13, the objective lens 5 is subjected to focusing control by the well-known astigmatism method, whereby movement control of the objective lens 5 in the optical axis direction (Z-axis direction) is performed. Further, the light transmitted through the other beam splitter 9 as it is is received by the two-division light receiving element 14, and the output signal thereof is sent to the objective lens actuator 13 via the control mechanism 12, whereby the objective lens 5 is operated by the push-pull method. Tracking control is performed, whereby movement of the objective lens 5 in the disc radial direction (X-axis direction) is controlled. If the focusing control and the tracking control are properly performed, the light spot can be focused and irradiated on the central portion of the recording surface-shaped track of the half mirror 15.

In this case, the half mirror 15 is positioned on the reference plane P by a microscope 18 including an objective lens 16 and a magnifying optical system 17. This microscope 18 is connected to a TV camera 19, which is a TV monitor 2.
0, so that the beam spot focused on the half mirror 15 can be observed.

[0004]

In this case, the assembling adjustment of the optical pickup 21 is performed by controlling the movement of the objective lens 5 by the objective lens actuator 13 so that the beam spot diameter on the TV monitor 20 becomes the best. Can be done accurately. However, it is very difficult to keep the focus position of the microscope 18 on the reference plane P. In order to observe a spot having a beam spot diameter of about 1 μm, it is appropriate that the magnification of the microscope 18 itself is 1000 times or more. In such a high magnification, the magnification of the objective lens 16 of the microscope 18 is increased. The distance from the reference plane P must be kept constant with an accuracy of submicron or less, but since the lens barrel of the microscope 18 is heavy and long, it is quite difficult to keep it with an accuracy of submicron or less. is there. In the conventional example (two publications) as described above, the assembly adjustment is performed by controlling the movement of the optical pickup 21 side, but it is still sufficient for improving the usability and the reliability of the assembly adjustment. It cannot be said that it is a thing.

[0005]

According to another aspect of the present invention, there is provided an optical pickup unit having a light source and an objective lens for condensing a beam emitted from the light source, and a beam condensed by the objective lens. A light-transmissive reference surface member having a reference step surface formed by concavities and convexities on a reference surface serving as a convergence point, and a condensing spot from the optical pickup unit transmitted through the reference surface member and illuminated by a light source for illumination. In an optical pickup assembly adjusting device including a microscope objective lens for observing a reference step shape and a monitor for observing a beam branched from the microscope objective lens, the microscope objective lens and the reference surface member And a fixing member for integrally holding the reference lens and the microscope objective lens and the reference surface member on the fixing member. It provided the reference plane varying mechanism capable of varying.

According to a second aspect of the present invention, in the first aspect of the present invention, the reference plane varying mechanism is configured to vary in the optical axis direction of the microscope between the objective lens for the microscope and the reference plane member according to the control signal. Variable control means were provided.

According to a third aspect of the invention, in the first aspect of the invention, the reference surface of the reference surface member is irradiated from the side of the microscope objective lens, and the reflected light is used to detect the focus signal of the reference surface. A reference plane focus detection optical system is provided.

According to a fourth aspect of the present invention, in the first aspect of the present invention, an image processing device for determining the position of the microscope objective lens from the reference plane image observed on the monitor through the microscope objective lens is provided. A reference plane variable control means for changing the distance between the reference plane member and the microscope objective lens to the focus position according to a control signal from the image processing apparatus is provided.

[0009]

According to the first aspect of the present invention, by keeping the distance between the reference plane and the microscope objective lens constant, it becomes difficult for the microscope focus shift to occur over time. Since the interval can be adjusted by an external input, it is possible to further improve the accuracy as compared with the conventional assembly adjustment.

According to the second aspect of the invention, the reference surface variable control means is provided, so that the reliability can be further improved as compared with the first aspect of the invention.

According to the third aspect of the invention, since the reference surface focus detection optical system is provided, the well-known focus error signal detection control can be performed, so that the responsiveness can be accelerated.

According to the fourth aspect of the present invention, by performing image processing, it is not necessary to newly install a detection system in the microscope, and it is possible to easily perform the assembly adjustment of the optical pickup.

[0013]

EXAMPLE A first example of the present invention will be described. Before entering the description of the specific configuration of the present invention, first, the basic operation principle of the assembly adjustment of the optical pickup using the microscope will be described with reference to FIGS. 4 and 5A to 5C. . When the distance between the objective lens 5 of the optical pickup 21 and the reference plane P is changed while the focus of the microscope 18 of FIG. 4 is fixed on the reference plane P, the light spot intensity (waveform 22) from the optical pickup 21 is changed. As shown in FIG. 5A, it becomes strongest when the objective lens position of the optical pickup 21 is in focus with respect to the reference plane P. Such intensity change is shown in FIG.
As shown in, the change in the difference between the maximum value and the minimum value of the track error signal obtained when the objective lens 5 of the optical pickup 21 is defocused while vibrating an optical disk (not shown) in the disk radial direction (X-axis direction) ( Waveform 23)
Corresponding to. The waveform 23 of this signal and the optical pickup 21
The focus offset amount Δ can be evaluated from the waveform 24 of the focus error signal. Therefore, such a FIG.
By using the correspondence relationship between the waveform 22 of (a) and the waveform 23 of FIG. 5 (b), as shown in FIG. 5 (c), the focus offset is calculated from the waveform 22 of the spot intensity and the waveform 24 of the focus error signal. By evaluating the amount Δ, since the disc surface is not vibrated, the defocus of the microscope 18 does not occur, the stability of the measurement system increases, and the accuracy of the assembling and evaluation of the optical pickup 21 using the microscope 18 is improved. It becomes possible. Therefore, for such a reason, a detailed configuration of the present invention will be described below. The description of the same parts as those of the conventional example (see FIG. 4) described above will be omitted.
The same reference numerals are used for the same portions.

Therefore, a specific structure of this embodiment will be described with reference to FIGS. 1 and 2 (corresponding to claims 1, 2 and 4). In the optical pickup assembling adjustment apparatus of FIG. 1, a reference step P, which is a converging point of a beam condensed by the objective lens 5 of the optical pickup 21 as an optical pickup unit, has a reference stepped shape formed by unevenness. A transparent reference plane member 25 is arranged. The reference surface member 25 is fixed to one end of a fixing member 26, and the microscope objective lens 27 is fixed to the other end side. A half mirror 28 is provided on the optical path behind the microscope objective lens 27.
Is disposed, and an illumination light source 29 is provided on the optical path in the latter stage after passing through the half mirror 28. in this case,
The objective lens 27 for a microscope is for observing a condensed spot from the optical pickup 21 that has passed through the reference surface member 25 and a reference step shape illuminated by the illumination light source 29. The reference surface member 25 and the fixing member 2
The microscope 6, the microscope objective lens 27, the half mirror 28, and the illumination light source 29 constitute a microscope 30.

A monitor 31 for observing the beam from the microscope objective lens 27 is arranged on the optical path reflected by the half mirror 28. This monitor 3
1 is connected to the image processing device 32. The output signal from the image processing device 32 is the CRT 33 and the CPU 34.
Sent to. The control signal from the CPU 34 is connected to a piezo power supply 35 as a reference plane variable control means.

FIG. 2 shows the structure of the reference plane changing mechanism 36. The reference plane changing mechanism 36 includes the fixing member 26.
And a piezo element 37 embedded in the fixing member 26. As a result, the distance T between the microscope objective lens 27 and the reference surface member 25 is set to the microscope optical axis direction Z.
Can be changed to.

In such a structure, the light condensed from the objective lens 5 of the optical pickup 21 is applied to the reference plane member 25 arranged on the reference plane P. The transmitted light of the emitted beam through the disc is condensed by the microscope objective lens 27, reflected by the half mirror 28, and is reflected by the monitor 3
Guided to 1. The reference plane image observed on the monitor 31 is sent to the CPU 34 via the image processing device 32, and it is determined whether or not the image is an image at the focus position. If it is not the focus position, the piezo power supply 35 is driven by using the focus signal of the reference plane focus to displace the reference plane changing mechanism 36 in the Z-axis direction, and the objective lens 27 for microscope and the reference plane member 25 are separated. By changing the interval T, the focus of the microscope 30 is adjusted so that it is always on the reference plane P.

As described above, the piezo power source 35 is used to displace the reference plane changing mechanism 36 to keep the distance between the reference plane P and the microscope objective lens 27 constant, thereby causing a microscope focus shift with time. It can be made difficult. Moreover, by adjusting the distance between the reference plane P and the microscope objective lens 27 by an external input, the microscope 30
Assembling and adjusting the conventional optical pickup using, and the accuracy of the adjusting device can be further improved,
The usability can be improved. In addition, by driving and controlling the reference plane variable mechanism 36 using the piezo power supply 35, the reliability of assembly adjustment can be further improved. Furthermore, since the image processing is performed by using the image processing device 32, the responsiveness is somewhat deteriorated, but it is not necessary to newly install a detection system in the microscope, and it is easy to install the optical pickup assembly adjustment device or the evaluation device in the microscope. It can be applied.

Next, a second embodiment of the present invention will be described with reference to FIG. 3 (corresponding to claim 3). The description of the same parts as those of the above-described first embodiment (see FIG. 1) is omitted, and the same reference numerals are used for the same parts. A half mirror 38 is arranged in the optical path between the microscope objective lens 27 and the half mirror 28 in the microscope 30. A reference plane focus detection optical system 39 is arranged on the optical path of the light reflected by the half mirror 38. In the reference plane focus detection optical system 39, a laser light source 40, a lens 41, a beam splitter 42, a cylinder lens 43, and a four-division light receiving element 4 are provided.
And 4 are provided. A reference plane focus control mechanism 45 is connected to the subsequent stage of the reference plane focus detection optical system 39. The reference plane focus control mechanism 45 is
It has a function of displacing the fixing member 26 in the Z-axis direction.

In such a structure, the laser light source 40
The light flux from the lens is in a state where the beam divergence tendency is matched with the light flux in the microscope 30 by the lens 41, the light flux is guided into the microscope 30 via the beam splitter 42, and is reflected by the half mirror 38 to be reflected by the microscope objective. Lens 2
The light is focused on the reference surface member 25 by 7. This condensed beam is then reflected and guided again into the reference plane focus detection optical system 39 via the microscope objective lens 27 and the half mirror 38. In this reference plane focus detection optical system 39, after passing through the beam splitter 42, astigmatism is given by the cylinder lens 43 and the light is received by the four-division light receiving element 44. The output signal from the four-division light receiving element 44 is sent to the reference surface focus control mechanism 45 to drive and control the reference surface variable mechanism 36 (see FIG. 2), thereby performing focusing control by the astigmatism method. The focusing control method is not limited to the astigmatism method, and other known control methods such as a knife edge method and a beam size method may be used.

As described above, by providing the reference surface focus detection optical system 39, the existing focus error signal can be detected, so that the responsiveness is fast and the reliability can be improved.

[0022]

According to the first aspect of the present invention, there is provided an optical pickup unit having a light source and an objective lens for condensing a beam emitted from the light source, and a converging point of the beam condensed by the objective lens. A light-transmissive reference surface member having a reference step shape formed by unevenness on the reference surface, a condensed spot from the optical pickup unit transmitted through the reference surface member, and the reference step shape illuminated by a light source for illumination. In an optical pickup assembly adjusting device including an objective lens for a microscope for observing and a monitor for observing a beam branched from the objective lens for a microscope, the objective lens for a microscope and the reference surface member are integrated. A fixing member for holding is provided, and the distance between the microscope objective lens and the reference surface member can be varied on the fixing member in the optical axis direction of the microscope. Is provided with the ability reference plane variable mechanism,
By keeping the distance between the reference surface and the microscope objective lens constant, it becomes difficult for the microscope to defocus over time, and the distance between the reference surface and the microscope objective lens can be adjusted by external input. Compared with the conventional assembly adjustment, the accuracy can be further improved and the usability can be further improved.

According to a second aspect of the present invention, in the first aspect of the present invention, the reference plane varying mechanism is configured to vary in the microscope optical axis direction between the microscope objective lens and the reference plane member in accordance with a control signal. Since the variable control means is provided, the reliability can be further improved as compared with the invention according to claim 1.

According to a third aspect of the present invention, in the first aspect of the invention, the reference surface of the reference surface member is irradiated from the side of the microscope objective lens, and the reflected light is used to detect the focus signal of the reference surface. Since the reference surface focus detection optical system is provided, the well-known focus error signal detection control can be performed, so that the responsiveness can be speeded up and the assembling reliability can be improved.

According to a fourth aspect of the present invention, in the first aspect of the present invention, an image processing device for determining the position of the microscope objective lens from the reference plane image observed on the monitor through the microscope objective lens is provided. Since the reference surface variable control means for changing the distance between the reference surface member and the microscope objective lens to the focus position according to the control signal from the image processing apparatus is provided, by performing the image processing in this way, It is not necessary to incorporate a detection system into a microscope, and it can be easily applied to an assembly adjustment device for an optical pickup or an evaluation device.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an optical pickup assembly adjusting apparatus that is a first embodiment of the present invention.

FIG. 2 is a side view showing a reference plane changing mechanism of a fixing member.

FIG. 3 is a block diagram showing a configuration of an optical pickup assembly adjusting device which is a second embodiment of the present invention.

FIG. 4 is a block diagram showing a configuration of a conventional optical pickup assembly adjusting device.

FIG. 5 is an operation explanatory view showing the basic operation principle of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 light source 5 objective lens 21 optical pickup 25 reference surface member 26 fixing member 27 microscope objective lens 29 illumination light source 31 monitor 32 image processing device 35 reference surface variable control means 36 reference surface variable mechanism 39 reference surface focus detection optical system P reference surface

Claims (4)

[Claims] 1. An optical pickup unit having a light source and an objective lens for condensing a beam emitted from the light source, and a reference step shape due to unevenness on a reference surface which is a converging point of the beam condensed by the objective lens. And a light-transmissive reference surface member, and a microscope objective lens for observing the reference spot shape illuminated by a condensing spot from the optical pickup unit transmitted through the reference surface member and the illumination light source. And a monitor for observing a beam branched from the microscope objective lens, in an optical pickup assembly adjusting device, a fixing member for integrally holding the microscope objective lens and the reference surface member, The fixing member is provided with a reference plane changing mechanism capable of changing the distance between the microscope objective lens and the reference surface member in the optical axis direction of the microscope. An optical pickup assembly adjusting device characterized by being eccentric. 2. The reference surface variable control means for changing the reference surface changing mechanism in the optical axis direction of the microscope between the microscope objective lens and the reference surface member according to the control signal. The optical pickup assembly adjusting device described. 3. A reference plane focus detection optical system for irradiating a reference plane of a reference plane member from the side of an objective lens for a microscope and using the reflected light to detect a focus signal of the reference plane. The optical pickup assembly adjusting device according to claim 1. 4. An image processing device for determining the position of the microscope objective lens according to a control signal from a reference plane image observed on a monitor through the microscope objective lens is provided, and from this image processing device to the focus position. 2. The optical pickup assembly adjusting apparatus according to claim 1, further comprising a reference surface variable control means for changing a distance between the reference surface member and the microscope objective lens.