JPH0417127A - Optical pickup device - Google Patents

Abstract

PURPOSE:To realize the fixed structure of an optical pickup inexpensively with excellent workability and high reliability by using the adjusting means of an adjusting plate so as to bend a bending part provided on a protective plate with elastic deformation. CONSTITUTION:A photodetector 35 is adhered onto an abutting face 36. This device is provided with an adjusting plate 33 having the adjusting means adjusting the photodetector 35 in the optical axis direction, a holding plate 50 moved freely in a plane intersecting orthogonally with the optical axis, and the protective plate 58 fitted to the holding plate 50 and the adjusting plate 53, pressing the photodetector 35 at a prescribed pressure in the direction of the abutting face 36, having the bending part 77 capable of elastic deforma tion and bending a bending part 77 with the adjustment of the adjusting means. Thus, the workability is improved and even when the photodetector 35 is exfoli ated from the adjusting plate 33 in the case of the adjustment or in the lapse of time, the photodetector is stably fixed and the reliability is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an optical pickup device, and particularly to a fixing structure for a photodetector.

[Conventional technology]

An example of the prior art will be explained based on FIGS. 3 to 5.

FIG. 3 is a plan view of a photodetector mounting part in a conventional optical pickup device. In the figure, 1 is an optical unit, 2 is a 4-split photodetector, 3 is a holding plate, and 4 is a conductive part 5. A flexible printed circuit board (hereinafter abbreviated as FPC) is attached with an adhesive 20, which will be described later.

6 is a lead part that outputs the electrical output from the photodetector 2 to a playback device (not shown), 7 is a terminal of the photodetector 2, which consists of eight terminals, and the soldering part 9 connects the electrically conductive part 5 of the FPC 4. and mechanically connected and fixed.

Reference numeral 8 denotes an adhesive for fixing the holding plate 3 to a predetermined position on the optical unit 1, whereby the photodetector 2 is positioned and fixed on the order of 1 micron using a known photodetector adjustment device.

In this figure, when assembling the photodetector 2 and the holding plate 3 or FPC
Positional deviation may occur by gaps m and n with 4.
For this reason, it took time to adjust the photodetector, and some adjustments could not be made if the deviation was large. To prevent this, it was necessary to assemble the parts carefully and precisely using assembly jigs.

FIG. 4(a) is a schematic explanatory diagram showing an astigmatism optical system using a half mirror as a conventional example, and FIG. 4(b) shows the photodetectors at positions O1, S, and O2 in FIG. 2, and FIGS. 2(C) and 2(d) are a vertical cross-sectional view and a cross-sectional view showing an example of the magnifying lens adjustment structure.

In the figure, 10 is a disk, 11 is an objective lens built into a known actuator, and 12 is a half mirror 11.
3 is a magnifying lens; 14 is a holder in which the magnifying lens 13 is installed; 15 is a spring that applies pressure to the holder 14; 16 is an adjustment groove provided on the outer periphery of the holder 14; and 17 is an adjustment provided in the optical unit 1. The hole 18 is an eccentric screwdriver for adjustment, and the hole 18 is a guide hole having approximately the same diameter as the outer diameter of the holder 14.

Hereinafter, in the configuration (H), the spot shape on the four-divided photodetector 2 becomes approximately circular at the focal position of position S. Using this property, move the photodetector 2 in the direction of the arrows X and Y to a position S where the light outputs on the patterns A, B, C, and D, each divided into four equal parts, are equal. , and by turning the eccentric driver 18 in the J direction, the magnifying lens 13
is adjusted in the D direction on the order of 1 micron. In case B, the adjustment is performed alternately in the X and Y directions and the D direction, and requires skill because it is a highly sophisticated adjustment.

FIG. 5 is a side sectional view of FIG. 3, in which 20 is a thermosetting adhesive with excellent heat resistance and adhesive strength, 21 is a side surface of the photodetector M2, and 22 is a side wall of the holding plate 3. .

In configuration B, the photodetector 2 is fixed in a floating state via the FPC 4, so it is not directly affected by external forces E and F.
, G, the photodetector 2 has a microscopic dimension a
, b, and C, and as a result, a deviation from the focus position S occurred, deteriorating the performance of the light=3 pickup device.

Furthermore, in order to prevent displacement due to environmental factors such as temperature and humidity over time, it is necessary to use a highly reliable adhesive 20 for fixing the FPC 4, which inevitably increases the cost. there were.

[Problem to be solved by the invention]

As described above, in the conventional configuration, a positional shift may occur by the gap mn between the photodetector 2 and the holding plate 3 or FPC 4 during assembly, and the photodetector 2 may be moved in the X, Y, and D directions. Positioning on the order of 1 micron requires extremely precise adjustment, which takes time and effort to adjust the photodetector.
There were cases where adjustments could not be made when the deviation was large.

In addition, since the photodetector 2 is fixed in a floating state via the FPC 4, when external forces E, F, and G are applied directly, the photodetector 2 will be displaced by minute dimensions a, b, and c, respectively. Therefore, a deviation from the focus position MS occurs,
The performance of the optical pickup device was deteriorated. In addition, the adhesive 20 for fixing the FPC 4 must be highly reliable in order to prevent displacement due to environmental factors such as temperature and humidity over time, which inevitably increases costs.

The present invention has been made to solve the above-mentioned problems, and provides an optical pickup device having an optical pickup fixing structure that is easy to work with, has high reliability, and is inexpensive.

[Means to solve the problem]

The optical pickup device according to the invention of B includes an adjustment plate having a photodetector adhesively fixed thereto and an adjusting means for adjusting the photodetector in the optical axis direction, and the optical pickup device is movable in a plane perpendicular to the optical axis. a holding plate, and a bending part that is attached to the holding plate and the adjusting plate to press the photodetector toward the contact surface with a predetermined pressure and is elastically deformable, and the bending part is elastically deformable by adjusting the adjusting means. It is equipped with a protection plate that bends the bent portion.

[Effect]

In the invention of B, the photodetector is adjusted in the optical axis direction by elastically deforming the bent portion provided on the protection plate using the adjustment means of the adjustment plate, so adjustment is easy and requires a high level of skill. You can easily adjust it without it. In addition, since the photodetector is pressed with a predetermined pressure in the contact direction by the protection plate, it can be stably held and fixed even if the photodetector comes off from the adjustment plate during adjustment or due to displacement over time. becomes possible.

〔Example〕

Hereinafter, one embodiment of the invention of B will be described based on FIGS. 1 and 2.

FIG. 1 is a side view of essential parts of the present invention, and FIG. 2 is an exploded perspective view thereof. In the figure, 30 is an optical unit incorporating optical components, 31 is its upper surface, 33 is an adjustment plate made of, for example, metal, 34 is a tapped hole formed on one end side;
35 is a photodetector, 38 is a contact portion as a light receiving portion thereof, 3
7 is the back side of the base, 38 and 39 are a pair of opposing side surfaces as positioning parts, 40 and 41 are also end faces, 42 is eight terminals bent at right angles at predetermined positions, 43 is the top surface, 4
4, 45, and 46 are through holes that guide the reflected light from the disk 10, 47 are recesses having positioning portions 48 that allow the light receiving portion of the photodetector 35 and the through hole 4B to be positioned in correspondence with each other, and 49 are recessed portions. The screw hole 34 is a screw hole formed on the opposite side of the recess 47, 50 is a rigid holding plate made of aluminum, for example, 51 is a flat part, and 52 is a holding plate 50 that comes into contact with the upper surface 31 of the optical unit 30. Lower surface of 53 flat part 5
1 is a flat part 51 on the other end side, a thin fixing part, 54 is a part of the taper formed between the flat part 51 and the fixing part 53, and 55 is an FPC at a position corresponding to the terminal 42. 58 is a protective plate made of a spring material such as stainless steel with a thickness of about 0.4 mm, which has a through hole 56 and a conductive part 57, and outputs an electrical signal from the photodetector 35 to a reproduction device (not shown). The through holes Boa, Bob, 60C260 are formed at both ends ssa, 59b.
e. A hemispherical convex portion 62 is formed on the central covering portion 61 so as to protrude in the direction of the photodetector I#38.

83a, 63b, 64, 85 springs, 6B is a through hole, 6
7. 88 is a through hole, 89 is a relief hole. Here, the convex portion 62 is provided so as to press the photodetector 35 with a predetermined pressure via the FPC 55 with the protective plate 58 attached to the adjustment plate using screws 83aP83b. Therefore, even if the adjustment plate 33 is deformed by rotation of the screw 64 or the adhesive of the photodetector 35 is peeled off over time, it can be stably held and fixed.

In addition, the pressing force of the protective plate 58 is set to, for example, about I kg, and within the adjustment range, the holding force of the photodetector 35 is set to, for example, 150 G, which is a pressing force that can withstand any impact. It is.

Furthermore, since the protection plate 58 protects the photodetector 35, it protects it from direct external force and prevents dirt, scratches, etc. Here, the adjustment means 70 is the adjustment plate 33. Protective plate 58. Screw 64. The fixing means 71 is composed of the retaining plate 50 and an adhesive 73 which will be described later.

Reference numeral 72 designates a soldering part, edges 3 and 74 an adhesive made of a known anaerobic UV adhesive, 76 a stepped part, and 77 a bent part, each of which is set, for example, to about 0.8 i:rewidth.

Reference numeral 78 indicates an adjustment section, which is, for example, about 1 mm. Since the configuration here does not use the magnifying lens 13,
The adjustment in the D direction of the conventional example is replaced by the adjustment in the N direction of the photodetector 35.

Further, 79 is a side surface of the adjustment plate 33, 80 is a side surface of the protection plate 58, 81 and 82 are both end surfaces of the protection plate 58, and 83 is the adjustment plate 3.
3, 84 is the end surface of the holding plate 50, 85 is the holding plate 50.
This is an aspect of

In the above configuration, adjustments in the X and Y directions and in the N direction are performed by rotating the screw 64 in the M direction and rotating the retaining plate to position the photodetector 35 in a predetermined position on the order of 1 micron using a known adjustment device. In this case, the photodetector 35 is brought into contact with the positioning part 48 and the side surface 38, the @ part 40 and the side surface 792, the side surface 7 and the side surface 80, the end surface 81 and the end surface 83, Side surface 80, side surface 85, and end surface 8
4 is positioned and assembled, there is no misalignment of the photodetector 35 with respect to the adjustment plate 33 during assembly. Therefore, even if this optical pickup device is attached to a known adjustment device, a signal is immediately output, and the adjustment Improved workability in that it is easy to perform
3 (Since this is fixed with adhesive, there is no positional fluctuation of the photodetector 35 due to external forces E, F, and G, which has the effect of improving reliability over time and in terms of environment such as temperature and humidity.

Further, in this example, there is no need to use an adhesive for the FPC 55, and since the Cζ and the protection plate 58 are also formed by press molding of a spring material such as stainless steel, the cost is also low.

Furthermore, if necessary, the engagement parts with the adjustment plate 33, holding plate 50, optical unit 30, protection plate 58, screws 63, 64, etc. can be bonded with a known adhesive to further stabilize the fixation. be.

Note that the positioning portion, adjustment plate 33, holding plate 55, bending portion 77, protection plate 58, and light detection II! 35
There is no need to limit the fixing structure of the adjusting plate 33, the fixing means of the retaining plate 50, and the adjusting means of the photodetector 35. For example, regarding the protective plate 58, it may be made of plastic. In short, it is sufficient to have functions equivalent to these.

[Effect of the invention] As explained above, according to the invention of Party B, the back surface or the light-receiving surface of the photodetector is used as the abutment surface, the photodetector is adhesively fixed on this abutment surface, and the photodetector is an adjusting plate having adjustment means for adjusting the optical axis in the optical axis direction; a holding plate movable in a plane orthogonal to the optical axis; The protective plate is provided with a protective plate that is pressed with a predetermined pressure in the direction of contact and has an elastically deformable bending part, which can be bent by adjusting the adjustment means, thereby greatly improving work efficiency. Since the photodetector is pressed against the adjustment plate by the protection plate with a predetermined pressure, even if the photodetector is peeled off from the adjustment plate during adjustment or over time, it can be stably held and fixed. A highly reliable optical pickup device can be provided.

[Brief explanation of the drawing]

FIG. 1 is a side view of essential parts showing an embodiment of the present invention, FIG. 2 is an exploded perspective view thereof, FIG. 3 is a plan view of a photodetector mounting part in a conventional optical pickup device, and FIG. ) is a schematic optical path diagram of an astigmatism optical system using a half mirror, (b)
The figure is a diagram showing the shape of the light spot in Figure 81, Figures (c) and (d) are longitudinal and cross-sectional views showing an example of the magnifying lens adjustment structure, and Figure 5 is a partial cutaway of Figure 3. It is a side sectional view shown in a cutaway cross section. In the figure, 30 is an optical unit, 33 is an adjustment plate, 3S is a photodetector, 50 is a holding plate, 58 is a protection plate, and 64 is an adjustment screw. Person Masuo Oiwa (2 others) O1 photon unit ('o), 14 (α)

Claims (1)

[Claims] An optical unit with built-in optical components, a photodetector that receives reflected light from the disk via this optical unit and outputs an electrical signal, and a back surface or light-receiving surface of this photodetector is used as a contact surface to detect the light. an adjusting plate having an adjusting means for adhesively fixing the detector on the contact surface and adjusting the photodetector in the optical axis direction; a holding plate movable in a plane orthogonal to the reflective optical axis; Protection that is attached to the holding plate and the adjustment plate and presses the photodetector toward the contact surface with a predetermined pressure, and has a bending part that can be elastically deformed, and the bending part is bent by adjustment of the adjustment means. An optical pickup device comprising: a plate.