JPH04205920A - Position adjusting mechanism for photodetector - Google Patents

Abstract

PURPOSE:To allow the adjustment of the position of a photodetector with a simple operation by adjusting the position of the photodetector in the plane perpendicular to the optical axis of a luminous flux and in the optical axis direction by 1st and 2nd adjusting means. CONSTITUTION:The 1st adjusting means for moving the photodetector 1 which receives the luminous flux condensed by a condenser lens 6 in the optical axis direction of the condenser lens 6 with respect to a fixing part where the condenser lens 6 is fixed and the 2nd adjusting means for moving the photodetector 1 within the plane perpendicular to the optical axis are provided. For example, the adjustment in an x-y direction with in the plane perpendicular to the Ax of the condenser lens 6 is executed by loosening bolts 15 and moving the entire part of a mounting block. The adjustment in a z direction which is the optical axis direction is executed by sliding a cylindrical body 17 with respect to the mounting block 4. The position of the photodetector 1 relative to the luminous flux is adjusted by the simple adjusting operation in this way and the change of the adjusting position with lapse of time is obviated.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a mechanism for adjusting the position of a photodetector in an optical head of an optical disc player or the like.

[Conventional technology]

In general, adjustment of a photodetector is performed about two ball axes, one in a plane perpendicular to the optical axis and one in the direction of the optical axis. Adjustment in the plane perpendicular to the optical axis is performed so that the reflected light from the optical disk enters the appropriate position within the detector, and adjustment in the optical axis direction is performed to ensure that the spot of the reflected light has an appropriate shape or size. It will be done so that it will be done. FIG. 10 is a perspective view of a conventional photodetector adjustment mechanism, FIG. 11 is a sectional view thereof, and FIGS. 12(a) and 12(b) are illustrations of adjustment. As shown in FIGS. 10 and 11, in the conventional adjustment mechanism, the adjustment plate 2 on which the photodetector 1 is fixed is aligned in an The position of the condenser lens L is adjusted in two axes directions, the axis and the y-axis, and
The position of the cylindrical body B to which is fixed is adjusted in two axial directions. In this way, the adjustment in the biaxial direction within the plane perpendicular to the optical axis and the adjustment in the optical axis direction are performed independently of each other.

[Problem to be solved by the invention]

However, according to the conventional adjustment method as described above, when trying to slide the cylinder B in two axial directions as shown in FIG. Body B may tilt. If the center of the light beam is tilted by an angle O with respect to the optical axis when the cylinder B is tilted by φ with respect to the optical axis, the spot position on the photodetector 1 is dx, where f is the focal length of the condensing lens L. There is a possibility that the spot moves by =ftanθ and the spot deviates from the photodetector 1. In this way, when moving the condensing lens, there is a problem that when the lens is tilted due to adjustment, the adjustment must be made again in the x-y plane, which takes time. . Additionally, Japanese Patent Application Laid-Open No. 63-268130 discloses an adjustment mechanism in which the optical axis direction of the photodetector is adjusted by attaching the photodetector to a flexible substrate and deforming the substrate using screws. has been done. However, in the mechanism disclosed in this disclosure, the position adjustment is performed by elastic deformation of the substrate, so there is a possibility that the adjusted position may change over time.

[Purpose of the invention]

This invention was made in view of the above problems,
It is an object of the present invention to provide a photodetector adjustment mechanism that can adjust the position of a photodetector with respect to a light beam with a simple adjustment operation and that does not change the adjustment position over time.

[Means to solve the problem]

In order to achieve the above object, the present invention moves a photodetector that receives the light beam condensed by the condensing lens in the optical axis direction of the condensing lens with respect to a fixed part to which the condensing lens is fixed. It is characterized by having a first adjustment means and a second adjustment means for moving the photodetector in a plane perpendicular to the optical axis.

[Implementation 11M! ] Hereinafter, the present invention will be explained based on the drawings. [First Embodiment] FIGS. 1 to 4 show a first embodiment of the present invention, in which FIG. 1 is a perspective view, FIGS. 2 and 3 are sectional views,
FIGS. 4(a) and 4(b) are explanatory diagrams of the adjustment operation. The photodetector position adjustment mechanism shown in this example is the condenser lens 6
The mounting block 4 is movable in a plane perpendicular to the optical axis Ax of the condensing lens 6 with respect to the fixed part 12 (see FIG. 2), and the photodetector 1 is held therein.
The cylinder body 17 is slidably attached to the optical axis Ax in the force direction. The mounting block 4 includes a distal end portion 7 that is loosely inserted into a mounting hole 12a formed in a fixing portion 12, and a mounting plate portion 11 that is connected to the rear end of this distal end portion and screwed to the fixing portion 12. Ru. Furthermore, a through hole having a circular cross section is formed in the mounting block 4 and passes through the center of the mounting plate portion 11 and the tip portion 7, and the cylindrical body 17 is inserted into this through hole. Furthermore,
A notch 10 is formed in the middle of the tip 7, and half of the cross section of the through hole is open to the outside at the notch 10. A flat abutment surface 18 is provided on one side of the cylinder 17.
is formed, and when the cylindrical body 17 is inserted into the through hole, the abutment surface 18 slightly protrudes from the notch lO. Reference numeral 20 denotes a leaf spring 20, and with the cylinder 17 inserted, bolts 25.25 are passed through holes 21.21 formed at both ends of the leaf spring 20, and bolts 25.25 are inserted into screws formed in the notch 10. By screwing into the hole 22, the cylindrical body 17 is fixed to the mounting block 4. The mounting block 4 to which the cylindrical body 17 is fixed has a distal end 7
is fixed to the fixing part 12 by inserting it into the mounting hole 12a and screwing the bolt 15.15 into the screw hole 13.13 of the fixing part 12 through the insertion hole 14.14 of the fixing plate part 11. Adjustment in the x-y direction within a plane perpendicular to the optical axis Ax of the condenser lens 6 is performed by loosening the bolt 15 and moving the entire mounting block. Adjustment in two directions, which are the optical axis directions, is performed by sliding the cylindrical body 17 relative to the mounting block 4. As shown in FIG. 4(a), by fixing the condensing lens and moving the photodetector 1, even if the cylinder is tilted due to movement, the amount of movement of the light flux on the photodetector is If it is small, especially if the cylinder 17 is tilted around the photodetector as shown in FIG. 4(b), no movement of the light beam will occur on the photodetector 1. Note that in the first embodiment, the photodetector is aligned with the optical axis Ax of the condensing lens.
In this configuration, the first adjustment means (cylindrical body 17) that is moved in the optical axis direction is provided on the second adjustment means (mounting block 4) that is moved in a plane perpendicular to the optical axis.

Second Embodiment FIGS. 5(a) to 5(d) show a second embodiment of the present invention. In the following embodiments, a second adjusting means for moving the photodetector in a plane perpendicular to the optical axis is provided on a first adjusting means for moving the photodetector in the direction of the optical axis of the condenser lens. This adjustment mechanism includes a fixed part 60 provided with a condensing lens (not shown), a mounting block 5 that is slidable in the optical axis direction 2 of the condensing lens with respect to the fixed part, and a photodetector l fixed and mounted. The block is composed of a substrate 2 that is movable within a plane perpendicular to the optical axis. The light beam from the condenser lens reaches the photodetector 1 through an optical path hole 47 in the fixed part and an optical path hole (not shown) formed in the mounting block 5 in communication with the optical path hole 47. The mounting block 5 is provided with guide bins 10a and lobs that protrude toward the fixed part along the optical axis direction, and the fixed part 60 is provided with guide holes 11a and Llb into which the guide bins are inserted. There is. The mounting block 5 connects the guide bins 10a, 10b to the guide holes 11a,
After the bolt 18 is inserted into the fixing part 60 and attached to the fixing part 60, the bolt 18 is screwed into the screw hole 48 of the fixing part through the elongated hole 46, thereby fixing it to the fixing part 60. On the other hand, the board 2 has two bolts 15 screwed into the mounting block 5 via the cutouts 3.3 provided at both ends.
．． 15, it is fixed to the mounting block 5. Adjustment in the Z direction is performed by inserting and engaging the eccentric pin 49a provided at the tip of the adjustment rod 49 into the adjustment hole 45 provided in the mounting block 5 with the bolt 46 loosened, and rotating the adjustment rod 49. let Since the eccentric bin 49a is provided at a position different from the center of rotation of the adjustment rod 49, the mounting block 5 can be moved by rotating the adjustment rod. Since the mounting block 5 is guided by guide bins provided at two locations relative to the fixed part,
There is no rattling when moving, and it moves smoothly. Adjustment in the x-y direction is carried out by moving the board 2 with the bolts 15.15 loosened.

[Third Embodiment] FIGS. 6(a) to (C) show a third embodiment of the present invention. In this embodiment, the optical axis (Z
A guide groove 50 having a 7-shaped cross section is formed along the axial direction, and a rail-like protrusion 51 having a 7-shaped cross section is formed on the mounting block 5B to be guided by this guide groove 50. Furthermore, two mounting holes 46a and 46b are formed in the upper surface of the mounting block 5B, and two screw holes 48a and 48b are provided in the fixing member 60B corresponding to these mounting holes. One screw hole 4
8b is provided at the guide groove 50 position. In this embodiment 1, the guide groove 5o and the protrusion 51 having a 7-shaped cross section are used to attach the mounting block 5B to the fixing member 60B.
The guidance is carried out smoothly. Also, one screw 1
8b is screwed onto the guide groove 5o and the mounting block 5B is fixed to the fixing member 60B, so the mounting block 5B does not shift relative to the fixing member 60B after adjustment, and the adjusted state does not change over time. do not have. The configuration, operation, and effects of other parts of the third embodiment are the same as those of the second embodiment already described.

Fourth Embodiment FIGS. 7(a) to (C) show a fourth embodiment of the present invention. In this embodiment, the mounting block 5C is formed in the shape of a rectangular parallelepiped, and is provided with guide bins loa, 1°b and an adjustment hole 45 as in the second embodiment. The fixing member 60C also has guide holes 11a through which these guide bins are inserted,
11b is formed, and a screw hole 25a125b communicating with the guide hole is provided on the top surface. And bolt 1
By screwing 8a and 18b into the screw holes, the tips of the bolts are brought into contact with the guide bottles 10a and 10b inserted into the guide holes, and the mounting block 5C is fixed to the fixing member 60C. The configuration, operation, and effects of other parts of the fourth embodiment are the same as those of the second embodiment already described. [Fifth Embodiment 1] FIGS. 8(a) to 8(c) show a fifth embodiment of the present invention. A cylindrical portion 30 that is pushed through the optical path hole 47 of the fixing portion 60D is formed in the rectangular parallelepiped-shaped mounting block 5D. On the outer circumferential surface of the cylindrical portion 30, flat portions 3 are provided at opposing positions in the upper and lower directions in the figure.
5a and 35b are provided, and one plane portion 35a is provided with an adjustment groove 52 extending in the X direction. Fixed part 60D
A recess 31 is provided on the upper surface of the recess 31, and an opening 32 communicating with the screw holes 25a, 25b and the optical path hole 47 is formed in the recess 31. The cylindrical part 30 of the mounting block 5D is connected to the optical path hole 4.
7, the flat portion 35a is exposed from the opening 32. Here, the mounting block 5D can be fixed to the fixing part 600 by threading the bolts 18a, 18a through the leaf spring 23 and into the screw holes 25a, 25b. For adjustment in two directions, an adjustment rod 49 is inserted into an adjustment hole 23a provided at the center of the leaf spring 23, and an eccentric pin 49a provided at the tip of the adjustment rod is engaged with an adjustment groove 52 of the cylindrical portion 30. By rotating the adjustment rod 49 in this state, the attachment block 5D can be moved. In this embodiment, by restraining the flat portion 35a with the leaf spring 23, adjustment in the Z-axis direction can be performed while preventing rotation of the mounting block 5D around the axis. The configuration, operation, and effects of other parts of the fifth embodiment are the same as those of the second embodiment. [Sixth Embodiment 1] FIGS. 9(a) to 9(c) show a sixth embodiment of the present invention. The mounting block 5E of this embodiment has a threaded portion 4 at the tip.
The fixing portion 60E has a cylindrical portion 30B having a diameter 0 formed therein, and a recess 42 for arranging a ring screw 41 that is screwed into the threaded portion 40. When attaching the mounting block 5E to the fixed part 60E, insert the ring screw 41 into the recess 4.
2, the cylindrical portion 30B is inserted into the optical path hole 47 via the spring 43, and the ring screw 41 is rotated to be screwed into the threaded portion 40. After properly rotating the ring screw and positioning it, the plate spring 23 is attached to the bolt 18a,
18b to the fixed part 60E, and press the flat part 35a of the cylindrical part 30B to attach the mounting block 5E to the fixed part 60E.
Fixed to. Adjustment of the photodetector 1 in two directions can be performed by rotating the ring screw 41. The configuration, operation, and effects of other parts of the sixth embodiment are the same as those of the fifth embodiment described above. [Effects of the Invention 1] As explained in detail above, according to the present invention, first,
The position of the photodetector can be easily adjusted by the second adjustment means in a plane perpendicular to the optical axis of the light beam and in the optical axis direction, especially when tilting occurs due to movement error when adjusting the optical axis direction. Also, there is less possibility that the light beam will deviate from the photodetector.

[Brief explanation of the drawing]

1 to 4 are diagrams explaining a first embodiment of the present invention, in which FIG. 1 is a perspective view, FIGS. 2 and 3 are sectional views,
FIGS. 4(a) and 4(b) are explanatory diagrams of the operation. FIGS. 5(a) to 5(d) are explanatory diagrams of the second embodiment, and (
(a) is a perspective view, (b) is a plan view of the substrate, (c) is an exploded perspective view, and (d) is a plan view of the fixing part. FIGS. 6(a) to 6(d) are explanatory diagrams of the third embodiment, and (
(a) is a perspective view, (b) is an exploded perspective view, and (c) is a plan view of the fixing part. FIGS. 7(a) to 7(d) are explanatory diagrams of the fourth embodiment, and (
(a) is a perspective view, (b) is an exploded perspective view, and (c) is a plan view of the fixing part. FIGS. 8(a) to 8(d) are explanatory diagrams of the fifth embodiment, and (
(a) is a perspective view, (b) is an exploded perspective view, and (c) is a plan view of the fixing part. FIGS. 9(a) to 9(d) are explanatory diagrams of the sixth embodiment, and (
(a) is a perspective view, and (b) is an exploded perspective view. Figures 10 to 12 show a conventional photodetector adjustment mechanism, with Figure 10 being a perspective view, Figure 11 being a sectional view, and Figures 12(a) and 12(b) showing an explanation of the adjustment operation. It is a diagram. 1... Photodetector 2... Board 5.5B, 5C15D15E... Mounting block 17... Cylindrical body

Claims (3)

[Claims] (1) a first adjusting means for moving a photodetector that receives the light beam condensed by the condenser lens in the optical axis direction of the condenser lens with respect to a fixed part to which the condenser lens is fixed; and second adjustment means for moving the photodetector in a plane perpendicular to the optical axis. (2) a mounting block that is moved in a plane perpendicular to the optical axis direction of the condenser lens with respect to a fixed part to which the condenser lens is fixed; and a mounting block that receives the light beam condensed by the condenser lens. A position adjustment mechanism for a photodetector, comprising a photodetector and a cylindrical body that is slidable in the optical axis direction with respect to the base. (3) A mounting block that is slidably provided in the optical axis direction of the condenser lens with respect to a fixed part to which the condenser lens is fixed, and a photodetector that receives the light beam condensed by the condenser lens. A position adjustment mechanism for a photodetector, comprising: a substrate movable relative to the base in a plane perpendicular to the optical axis.