JPH043006A - Fine adjusting mechanism for optical element of optical pickup - Google Patents

Abstract

PURPOSE:To allow the fine adjustment of the mounting position of the optical element with ease in a short period of time by providing at least two projections or holes on either one or both of a holding member and fixing member. CONSTITUTION:The two projections 12C or holes are provided in either one or both of the holding member 11 and fixing member 12 so that the mounting position of the optical element 10 can be finely adjusted in the two directions intersecting orthogonally with each other on the prescribed mounting plane by the principle of the lever utilizing these projections 12C and/or holes. Namely, an adjusting rod 14 is inserted into the two projections 12C or holes and force is applied to the members by the principle of the lever, by which the members are moved. The fine adjusting mechanism to allow the easy fine adjustment of the mounting position of the optical element is inexpensively obtd. in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fine adjustment mechanism for finely adjusting the mounting position of an optical element incorporated in an optical pickup or the like of an information recording/reproducing device on a predetermined mounting plane.

[Conventional technology]

In optical big amplifiers of information recording and reproducing devices, there are parts where it is necessary to finely adjust the mounting position of the element relative to the optical axis on a predetermined mounting plane. On the other hand, there is a part that finely adjusts a light emitting element (LD; laser diode) or a polarizing prism, and a part that finely adjusts a light receiving element (photodetector) for light reflected from a recording medium.

FIG. 8(a) is a diagram showing an example of an optical pickup of an information recording/reproducing apparatus having such a portion, and 50 in the figure is a laser diode as a light emitting element. The diffused light beam emitted from the laser diode 50 is made into a parallel light beam by a collimator lens 51, and is then converted into a parallel light beam by a polarizing beam splitter 52, l.
The light passes through the /4 wavelength plate 53, is focused by the objective lens 54, and enters the recording surface of the recording medium 55.

The reflected light from the recording medium 55 passes through the objective lens 54 and the 1/4 wavelength plate 53 and enters the polarizing beam splitter 52, where the direction is changed by 90 degrees and enters the 1/2 wavelength plate 56, where the P-polarized light is The light is made into a light beam and enters the reflective surface of the critical angle prism 57. The light beam reflected by the critical angle prism 57 and whose direction has been changed by 90 degrees enters a 4-split photodiode 58 as a light receiving element, as shown in arrow A in FIG. 8(a). form a light spot. Here, the signals from each part of the photodiode 58 are input to A, B, and C.
, D, the focus error signal is extracted by ((A+D) - (B+C) ), and ((A+8) -
The tracking error signal is extracted by (C+D)), and the information signal is extracted by (^1B+C+D).

By the way, in order to suppress the occurrence of aberrations in the light spot focused by the objective lens 54, which affects the characteristics of the optical pickup, it is necessary to prevent the light beam incident on the objective lens 54 from being obliquely incident. The position 50a of the light emitting point of the laser diode 50 is set by the collimator lens 51.
Fine adjustment is required to accurately align the optical axis. In addition, in order to obtain good focus servo characteristics and tracking servo characteristics of the objective lens 54 with respect to the recording medium 55, the objective lens 54 must have no electrical offset and the focus direction (vertical direction in the paper) must be ( (A+D)
-(B+C) 1-0, and regarding the tracking direction (direction penetrating the paper), ((A0B)-(C+D
) ) 4-split photodiode 58 so that -〇
It will be necessary to fine-tune the position of.

Conventionally, such fine adjustments have been made as follows. That is, as shown in FIGS. 9(a) and 9(c), an optical element 60 such as a light emitting element and a light receiving element is coupled to a holding member 61, and the holding member 61 is fixed with two screws 62 at diagonal positions. In the case of a configuration in which the holding member 61 is fixed to the member 63, the holding member 61 is fixed to the screw 62.
When loosened slightly, it becomes possible to move on the mounting plane within the play between the spear head 2 and the screw through hole 61a provided in the holding member 61, so the diagonal positioning provided in the holding member 61 The holding member 61 was moved to the desired position by moving the adjustment jig 65 in which two pins 64 were embedded, the tip of which was provided with a tapered portion that engaged with the hole 61b. (This is determined by actually operating the optical system and checking the output signal of the optical element), and then the screw 62 is completely tightened to complete the fine adjustment. The adjustment jig 65 is connected to a spring-type moving stage (hereinafter referred to as a stage) having a guide mechanism (not shown), and by operating this stage, one part of the optical element 60 is indirectly adjusted via the adjustment mechanism 64. You can make fine adjustments to the direction.

[Problem to be solved by the invention]

When performing fine adjustment using the above method, the distance between the two pins 64 of the adjustment jig 65 and the angle formed by them are
If the distance between the two positioning holes 61b and the angle they form do not match, the pin 64 and the positioning hole 61b will not be fully engaged and the holding member 61 will not move in the intended adjustment direction. Since it rotates, it is necessary to repeatedly make fine adjustments, which increases the adjustment time. Also, since the above stage can only be finely adjusted in one direction,
Two stages are required for fine adjustment of the direction, and such complicated stages and adjustment jigs result in increased costs. Since it takes a lot of time, the adjustment time becomes even longer.

The present invention has been made by focusing on the problems of the conventional example, and an object of the present invention is to provide a fine adjustment mechanism that can easily finely adjust the mounting position of an optical element using the lever principle. .

[Means and effects for solving the problem] For this purpose, the fine adjustment mechanism for the optical element in the optical pickup of the present invention moves the holding member that holds the optical element in the optical pickup on a predetermined mounting plane of the fixing member. A mechanism that finely adjusts the mounting position of an optical element by moving it, wherein at least two projections or holes are provided on one or both of the holding member and the fixing member, and the projections and/or holes are used to provide a lever. According to this principle, the mounting position of the optical element can be finely adjusted in two directions perpendicular to each other on the predetermined mounting plane.

As a result, the optical element can be mounted by inserting the adjustment rod into at least two protrusions or holes provided on one or both of the holding member and the fixing member of the optical pickup and moving it by applying force based on the lever principle. A fine adjustment mechanism that can easily and quickly finely adjust a device in two mutually orthogonal directions on a predetermined mounting plane can be provided at low cost.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIGS. 1(a) and 1(b) are diagrams showing the configuration of a first embodiment of the present invention, in which numeral 10 indicates an optical element in an optical pink amplifier.

The optical element 10 is held by a holding member 11, as shown in FIG. 1(a).
As shown in FIG. 3C, which is a cross-sectional view taken along line Ii of FIG.

The holding member 11 is fixed on the mounting plane 12b of the fixing member 12 by two diagonally positioned screws 13. Note that instead of the screws 13, springs are used to attach the holding member 11 to the fixing member 1.
2 may be used.

In this example, on the mounting plane 12b of the fixing member 12,
Two rectangular parallelepiped projections 12c as shown in the figure are provided so as to extend integrally in the adjustment direction (X direction, Y direction). These protrusions 12c are spaced apart from the holding member 11 by a dimension 11 so as to be parallel to the four sides of the holding member 11, and the height dimension 1□ is approximately the same as the thickness of the holding member 11c.

The holding member 11c and the four protrusions 12c constitute grooves in the X and Y directions, and at least two of the four grooves (X
, one location in the Y direction) as shown in FIG. 1(b) to finely adjust the mounting position of the optical element 10. In addition to the rectangular shape shown in Fig. 3(a), the cross-sectional shape of the adjustment rod may be a rectangular shape with both ends rounded, or a rectangular shape with the middle part rounded, as shown in Fig. 3(b) to (d). It is possible to use a rectangular shape that is hollowed out by a predetermined dimension, or a rectangular shape whose middle part is hollowed out by a predetermined dimension and whose both ends are further rounded.

The principle of the above fine adjustment will be explained with reference to FIG. Here, the dimension from the upper end of the adjustment rod 14 to the fulcrum S is Ll, the dimension from the fulcrum S to the lower end is F2, the angle that the adjustment rod 14 makes with respect to the holding member 11 is θ, the force applied to the adjustment rod 14 is FI, The force pushing the holding member 11 is F2, and the horizontal component of force F2 is F2.
Then, due to the lever principle, P, XLl = F2 XLz
-(1) F=Fzcos θ=L
I/L2 ・FIcos θ −(2).

In addition, in FIG. 2, the adjustment rod 14 may be tilted to the right so that the fulcrum S is at the lower end of the adjustment rod 14 (in that case,
(This is similar to the case shown in Fig. 5, which will be described later.) At this time, it is not a good idea to make the angle θ too large because the value of cos θ becomes small, so the above dimensions are adjusted so that the angle θ is 30 degrees or less. Set. As a result, the minimum value of cos θ is cos 30"; 0.87, which is close to 1. Therefore, if dimension L1 is made sufficiently long relative to dimension L2, the result will be as shown in Figures 3 (a) to (d). Adjustment dedicated to 1
The cross-sectional shape of 4 is the groove dimension 1. The force F1 can be sufficiently transmitted by making the longitudinal dimension sufficient for
It is possible to generate a force F that can move the holding member 11 which is lightly fastened and temporarily fixed, and at this time, the holding member 11 does not rotate.

Next, a specific method of this fine adjustment will be explained. First, as shown in FIG. 1(a), as described above, the holding member 1 is
1 is temporarily fixed, apply force to the adjustment rod 14 at at least one location in the X direction and one location in the Y direction of the groove formed between the holding member 11 and the protrusion 12c to tilt the adjustment rod 14 as appropriate. Make fine adjustments based on the principle of Next, with the optical element 10 at the desired mounting position, the two screws 3 are fully tightened to complete the fine adjustment. At this time, by fully tightening the screw 13 with the adjustment rod 14 inserted into the groove, it is possible to avoid misalignment during final tightening after fine adjustment and the need for repeated fine adjustment work. , the fine adjustment is completed in one time.

In this way, fine adjustment of the optical element mounting position in the intended adjustment direction (X, Y direction) can be easily and quickly performed using the lever principle, and such a fine adjustment mechanism is similar to conventional examples. Since it has a simple configuration that does not require a complicated stage or adjustment jig, significant cost reductions can be achieved.

FIGS. 4(a) and 4(b) are diagrams showing the configuration of a second embodiment of the present invention, and the same parts as in the first embodiment are given the same reference numerals.

The difference between this example and the first example is that the fine adjustment mechanism is formed of a hole instead of a protrusion, and other aspects are almost the same. That is, on the mounting plane 12b of the fixing member 12, the fourth
As shown in Figure (a) (a cross-sectional view of Figure (b)), an elongated hole 12d forming a groove with a depth of 13 is extended in the adjustment direction (X direction, X direction). Two holes are provided in each hole, and adjustment rods 14 are inserted into at least two of these four elongated holes (one on each side in the X and Y directions) to finely adjust the mounting position of the optical element IO. be.

To explain the principle of this fine adjustment with reference to Fig. 5, the adjustment rod 1
The total length of 4 is 1, and the dimension from the point of action S' to the bottom end is L4.
, the angle that the adjustment rod 14 makes with respect to the fixed member 12 is θ, the force applied to the adjustment rod 14 is F3, and the force pushing the holding member 11 is F
4. If the horizontal component of force F4 is F', then according to the lever principle, p3xL'l・F4 xL4 .
・(3)F'=Pacosθ=L3/L4 ・F3c
If you make osθ river (4) sufficiently long, the holding member 11 temporarily fastened by lightly tightening the screw 13 can be moved in the same way as the principle shown in Fig. 2. A force F' can be generated.

This fine adjustment is carried out using the same specific method as in the first embodiment described above, and thereby the same effects as in the first embodiment can be obtained.

FIGS. 6(a) and 6(b) are diagrams showing the configuration of a third embodiment of the present invention, in which the same parts as in the first embodiment are given the same reference numerals.

The difference between this example and the first example is the configuration of the fine adjustment mechanism, and other aspects are almost the same. That is, the sixth
As shown in Figure (b), which is a cross-sectional view taken along the line ■-■ in Figure (a), an elongated hole 11a forming a groove with a depth of 14 extends in the adjustment direction (X direction, X direction). Correspondingly, rectangular parallelepiped projections 12e are provided on the mounting plane 12b of the fixing member 12 so as to extend in the adjustment direction (X direction, X direction), as shown in FIG. As shown in FIG. 2, the protrusion 12e is positioned approximately at the center of the elongated hole 11a to form two grooves parallel to each other in the X and X directions.

By using these grooves and performing fine adjustments in the same manner as in the first embodiment according to the principles shown in FIG. 2 or 5, the same effects as in the first embodiment can be obtained. At this time, in this example, when performing fine adjustment in the X direction, for example, the optical element 10
In order to return the holding member 11 that has been moved too far downward as shown in FIG. 6(b), the adjustment rod 14 penetrates into the lower groove of the two grooves for fine adjustment. The first and second
Considering that in order to do the same thing in the embodiment, it is necessary to move the adjustment rod 14 to the groove portion of the dowel holding member 11 that is opposite to the optical element 10 and is separated by the width dimension, the amount required for fine adjustment is The effect is that the time required to move the adjustment rod can be shortened.

FIGS. 7(a) and 7(c) are diagrams showing the configuration of a fourth embodiment of the present invention, in which the same parts as in the first embodiment are denoted by the same reference numerals.

The difference between this example and the first example is the configuration of the fine adjustment mechanism, and other aspects are almost the same. That is, the seventh
As shown in figure (b), which is a cross-sectional view taken along the line IV-IV in figure (a), the elongated size 11b forming a groove with a depth of 15 extends in the adjustment direction (X direction, X direction). One each is provided, and elongated holes 12f extending in the adjustment direction (X direction, X direction) forming grooves with a depth of 16 in the fixing member 12 are provided at substantially the same positions as these elongated holes llb. It goes without saying that the elongated hole 11b is provided at a position that does not interfere with the attachment of the optical element 10.

By using these grooves 11b to 12f and making fine adjustments in the same manner as in the first embodiment according to the principle shown in FIG. 2 or 5, the same effects as in the first embodiment can be obtained.
As described in the third embodiment, when fine adjustment is performed by moving the holding member 11 back and forth in the adjustment direction, the effect is that the time required to move the adjustment rod can be further shortened than in the third embodiment. is obtained.

Note that the present invention is not limited to the above-mentioned example, and many modifications and changes are possible.

For example, in each of the above embodiments, the optical element is indirectly moved by moving the holding member 11 of the optical element, but if the optical element and the holding member are integrated, the mounting part of the optical element Can you provide a fine adjustment mechanism similar to the one above and move the optical element directly? jIt should be adjusted. Also the first
Similar effects can be obtained even if the cross-sectional shape of the rectangular parallelepiped projection provided on the fixing member 12 in the third embodiment is changed from a rectangular shape to a shape as shown in FIG. 3(C). Furthermore, similar effects can be obtained by making the elongated portion of the fixing member 12 pass through the fixing member 12 in the second and fourth embodiments, or by changing its cross-sectional shape as appropriate.

(Effects of the Invention) As explained above, according to the present invention, at least two protrusions or holes are provided on one or both of the holding member and the fixing member. This makes it possible to easily and quickly fine-tune the mounting position of the optical element in two directions perpendicular to each other on a predetermined mounting plane.Furthermore, there is no need for expensive stages or adjustment jigs as in conventional methods, making it possible to significantly adjust the mounting position of the optical element. Cost reduction can be achieved.

[Brief explanation of the drawing]

FIGS. 1(a) and (b) are diagrams showing the configuration of the first embodiment of the present invention, FIG. 2 is a diagram for explaining the principle of fine adjustment in the same example, and FIGS. 3(a) to ( (i) is a diagram illustrating the cross-sectional shape of the adjustment rod in the same example, FIG. 4 (a), Φ) is a diagram showing the configuration of the second embodiment of the present invention, and FIG. Figures for explaining the principle; Figures 6(a) and 6(b) are diagrams showing the configuration of the third embodiment of the present invention; Figures 7(a) and Φ) are diagrams of the fourth embodiment of the present invention. The diagrams showing the configuration, FIGS. 8(a) and 9(a) and 9(b), are diagrams for explaining the prior art. 10... Optical element 11... Holding member 11
a, 11b...Elongated hole 12...Fixing member 12
b...Mounting plane 12c, 12e...Protrusions 12d, 12f...Elongated hole 14...Adjustment rod 13...Screw Figure 1 (a) 2c Patent applicant Olympus Optical Industry Co., Ltd.

Claims (1)

[Claims] 1. A mechanism for finely adjusting the mounting position of an optical element by moving a holding member that holds the optical element in an optical pickup on a predetermined mounting plane of a fixing member, the mechanism comprising one or both of the holding member and the fixing member. At least two protrusions or holes are provided in the optical element, and the mounting position of the optical element can be finely adjusted in two directions orthogonal to each other on the predetermined mounting plane using the lever principle. A fine adjustment mechanism for an optical element in an optical pickup, characterized by: