JP2008243308A - Optical pickup - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thin optical disk device having a small interval between an optical disk and an optical pickup by preventing a bent part of a retaining spring from protruding from the optical pickup. <P>SOLUTION: The optical disk device is provided with a plate-like heat radiation part 25 provided on a surface in the direction opposite to the direction of emitting a laser beam oscillated by a laser unit 24 to radiate heat generated from the laser unit 24, an optical bench 23 for holding the laser unit 24 rotatably, and the retaining spring 26, wherein one end is fixed to the optical bench 23 and the other free end is pressed by the plate-like heat radiation part 25. A convex part 30 is formed on either the retaining spring 26 or the plate-like heat radiation part 25, an engagement hole 32 is formed on the other, and the convex part 30 comes into contact with the edge part of the engagement hole 32. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical pickup used in an optical disc apparatus that irradiates an optical disc with laser light and performs at least one of reading and writing of data.

  As shown in FIG. 18, a conventional optical pickup has a laser unit 52 inserted into an optical bench 51 and this state is held by a presser spring 53.

That is, the presser spring 53 is installed in parallel with the optical bench 51 and the free end 54 is bent into an L shape at the bent portion 55 so as to face the shield case 56 provided on the back of the laser unit 52. The convex portion 57 formed on the free end 54 is pressed into contact with the shield case 56 so as to make point contact (see, for example, Patent Document 1).
JP 2001-266387A

  In the conventional optical pickup, the convex portion 57 formed on the free end 54 of the presser spring 53 is in pressure contact with the shield case 56. Therefore, when the contact point between the convex portion 57 and the shield case 56 is shifted during assembly, FIG. As shown in FIG. 4, there is a possibility that the portion 58 of the presser spring 53 parallel to the optical stage 51 is deformed toward the optical disc 59 and the bent portion 55 protrudes toward the optical disc 59. For this reason, an interval corresponding to deformation is required between the optical pickup and the optical disk 59, and there is a problem that the entire optical disk apparatus cannot be thinned accordingly.

  To deal with this problem, it is conceivable to reduce the elasticity of the presser spring 53 so that the convex portion 57 slides on the surface of the shield case 56 even if there is a slight dimensional variation during assembly. The holding of the laser unit 52 with respect to the base 51 becomes uncertain, and an inadvertent rotation of the laser unit 52 occurs.

  On the contrary, if the elasticity of the presser spring 53 is increased, the laser unit 52 is surely held, but the above-described problems occur.

  The present invention has been made to solve the conventional problems, and is a thin optical disk device that can reduce the distance between the optical disk 59 and the optical pickup by making it difficult for the bent portion 55 of the holding spring 53 to protrude from the optical pickup. The purpose is to provide.

  The optical pickup of the present invention is for achieving the above object, and is provided with a laser unit that oscillates laser light, and a surface opposite to the emission direction of the laser light oscillated by the laser unit. A heat dissipating part that radiates heat generated from the optical unit, an optical base on which the laser unit is rotatably held, a holding spring having one end fixed to the optical base and the other free end pressed against the heat dissipating part, A convex portion is formed on one of the pressing spring and the heat radiating portion, and a hole is formed on the other, so that the convex portion and the edge of the hole are in contact with each other. Therefore, no deviation occurs in the pressing portion of the holding spring with respect to the heat radiating portion.

In the present invention, the convex portion is formed on one of the holding spring and the heat radiating portion, the hole is formed on the other, and the convex portion and the edge of the hole are in contact with each other, so that the frictional force of the contact is improved. As a result, as compared with the conventional optical pickup, the position of the pressing spring is easily determined, and the bent portion of the pressing spring is difficult to protrude from the optical pickup. According to the optical pickup of the present invention, a thin optical disk device in which the distance between the optical disk and the optical pickup is reduced can be provided.

  The present invention includes a laser unit that oscillates laser light, a heat radiating unit that is provided on the back surface of the laser unit in a direction opposite to the emission direction of the laser light oscillated by the laser unit, and radiates heat generated from the laser unit; An optical bench on which the laser unit is pivotably held, and a holding spring whose one end is fixed to the optical bench and the other free end is pressed against the heat radiating portion, are convex to either the holding spring or the heat radiating portion. This is an optical pickup in which a portion is formed, a hole is formed on the other side, and the convex portion and the edge of the hole are in contact with each other.

  The convex portion is in point contact with the edge of the hole, and the width of the edge of the hole in point contact with the convex portion is made larger than the width of the convex portion.

  The convex portion can contact the edge of the hole with a line. It is conceivable as an embodiment that the convex portion is formed in a spherical shape.

  Further, it is conceivable as an embodiment that the convex portion is spherical and the hole is formed in a true circle. At this time, since the convex portion is in line contact with the edge of the hole, the frictional force of the contact is further improved as compared with the point contact.

  It is also conceivable as an embodiment that the holding spring is formed in an L shape along the optical bench and has a bent portion bent at a predetermined radius of curvature.

  It is also an effective embodiment that the optical pickup of the present invention is used in an optical disc apparatus that irradiates an optical disc with laser light oscillated by a laser unit and performs at least one of data reading and writing.

Example 1
Embodiment 1 of the present invention will be described below with reference to the drawings.

  In FIG. 1 to FIG. 3, the car audio device 1 includes an optical disc device 2 having an optical pickup 3, a radio receiver 4, and a cassette tape recording / reproducing device 5. Unit 7, an adjustment knob 8 for power on / off and volume adjustment, an optical disk insertion / removal port 9 for inserting an optical disk into / from the optical disk device 2, a tuning knob 10 for radio, and a cassette tape insertion port 11 are provided. ing.

  In the main body 13 of the optical disc apparatus 2, six trays 14 for placing the optical disc 12 are arranged so as to be movable up and down. The optical disc device 2 irradiates the optical disc placed on the tray 14 with the laser beam oscillated from the optical pickup 3 to perform at least one of reading and writing of data. A lifting plate 15 having a shape surrounding the tray 14 is provided outside the tray 14. A desired tray 14 can be selected by moving the elevating plate 15 up and down, and a work space S having a predetermined height can be provided.

  Further, the rotation arm 17 is provided so as to be rotatable in the direction of arrow A about the support shaft 16, and is provided so as to be movable up and down along the support shaft 16.

  The rotating arm 17 includes a flat suspension chassis 18, a turntable 19, the optical pickup 3, a drive motor 20, and a lead screw 21. A base end side of the suspension chassis 18 is rotatably supported by the support shaft 16, and a turntable 19 that rotates while holding the optical disk 12 is provided at the distal end portion of the suspension chassis 18. In addition, the suspension chassis 18 is provided with an optical pickup 3 that oscillates a laser beam applied to the optical disk 12.

  The suspension chassis 18 includes a drive motor 20 and a lead screw 21 for reciprocating the optical pickup 3 along the suspension chassis 18.

  With respect to the car audio apparatus 1 configured as described above, an operation when music recorded on the optical disk 12 is reproduced will be described.

  First, the optical disk 12 inserted from the optical disk insertion / removal port 9 is placed on the tray 14. A plurality of optical disks 12 can be inserted. When the user operates the specific optical disk 12 to be reproduced by the operation switch provided on the front panel 6, the tray 14 is placed so that the work space S having a predetermined height is provided below the specified optical disk 12. Moving. Simultaneously with the movement of the tray 14, the rotating arm 17 is moved up and down so as to correspond to the work space S.

  The rotary arm 17 is moved up and down and then moved around the support shaft 16 to a predetermined reproduction position on the optical disk 12. Thereafter, a laser beam is oscillated from the optical pickup 3 provided on the rotating arm 17 and applied to the optical disk 12.

  After the oscillation of the laser light, the optical disk 12 is rotated by the turntable 19. The optical pickup 3 receives the laser beam reflected by the optical disk 12 while moving along the chassis 18. Data recorded on the optical disc 12 is decoded based on the received laser beam and reproduced as music.

  As shown in FIGS. 4 to 6, the optical pickup 3 includes an objective lens 22, an optical bench 23, a laser unit 24, a plate-like heat radiation portion 25, and a pressing spring 26.

  The laser unit 24 includes an oscillation element for oscillating a laser beam (not shown) and a light receiving element that receives the laser beam and converts it into an electrical signal.

  Laser light oscillated from the laser unit 24 passes through an optical element such as a prism (not shown) built in the optical bench 23 and is irradiated from the objective lens 22 onto the optical disk 12.

  Further, the laser unit 24 includes a plate-like heat radiating portion 25 on a portion opposite to the laser light emitting direction, that is, on the back surface. Since the laser unit 24 generates heat due to the current flowing to the oscillation element and the light receiving element of the laser beam and is sealed with resin, it has a structure in which heat tends to be trapped inside. Is radiated.

  The laser unit 24 is fitted in the optical table recess 28 of the optical table 23 in a state where the rotation can be adjusted. Further, the plate-like heat radiation portion 25 provided in the laser unit 24 is pressed by a pressing spring 26 from the direction opposite to the laser beam emission direction toward the laser beam emission direction. As a result, the laser unit 24 is rotatably held in the optical table recess 28 of the optical table 23.

The presser spring 26 is installed in parallel with the optical table 23 and is locked to the optical table 23 by a locking claw 29. The free end 26 a of the presser spring 26 is bent into an L shape at the bent portion 31, faces the plate-like heat radiation portion 25 provided at the back of the laser unit 24, and is a convex portion formed at the free end 26 a. 30 is in contact with the plate-like heat radiation part 25. The plate-like heat radiating portion 25 is formed with an engagement hole 32 which is a through hole for making phase contact with the convex portion 30.

  An adjustment hole 27 is further formed in the plate-like heat radiation portion 25. An adjustment pin (not shown) is inserted into the adjustment hole 27. By rotating the adjustment pin, the plate-like heat radiating portion 25 rotates, and accordingly, the laser unit 24 integrated with the plate-like heat radiating portion 25 also rotates. By rotating the laser unit 24, the grating adjustment is performed to finely adjust the position of the laser beam irradiated to the optical disk 12 when the optical pickup 3 is assembled.

  After the grating adjustment, the adjustment pin is removed and the laser unit 24 is fixed to the optical bench 23 with an adhesive. The holding spring 26 serves to prevent the position of the laser unit 24 from moving from the position at the time of the grating adjustment until the laser unit 24 is fixed to the optical bench 23 with an adhesive after the adjustment pin is removed. Have. For this reason, the holding spring 26 needs to have enough elasticity to have a predetermined torque or more when the adjustment pin is rotated.

  The engagement between the convex portion 30 and the engagement hole 32 will be described in detail with reference to FIGS. 7 and 8.

  As shown in FIG. 7, the holding spring 26 has a bent portion 31 and is provided along the optical bench 23. The direction in which the laser unit 24 oscillates the laser light is the direction of arrow B, and a plate-like heat radiating portion 25 is provided on the back surface of the laser unit 24 in the direction opposite to the arrow B.

  The convex portion 30 is formed in a hemispherical shape, and makes point contact with the edge of the engagement hole 32 formed in the plate-like heat radiating portion 25 at the contact 33 and the contact 34. Since the convex portion 30 is hemispherical, the cross section thereof becomes a circle having a predetermined radius K as indicated by a broken line 35 in FIG. Since the cross section of the convex part 30 is circular, the plate-shaped heat radiation part 25 can be rotated.

  For example, the engagement hole 32 is formed in a rectangular shape having a predetermined length L as a short side. The predetermined length L is twice the radius K of the convex portion 30, that is, the same size as the diameter of the cross section of the convex portion 30. Moreover, the width of the long side of the engagement hole 32 is larger than twice the radius K which is the width of the convex part 30, and the engagement hole 32 becomes a rectangle. The convex portion 30 makes point contact with the long side of the engagement hole 32 formed to be rectangular.

  When the heat radiating part 25 is provided on the back part of the laser unit 24, processing variations may occur. If the position of the engagement hole 32 is shifted due to processing variations, the protrusion 30 cannot be engaged with the engagement hole 32. However, when the engagement hole 32 is formed in a rectangular shape and is brought into point contact with the convex portion 30, a margin can be provided in the direction of the long side. Thereby, even if the engagement hole 32 is displaced in the long side direction due to processing variations, the convex portion 30 can be engaged with the engagement hole 32.

  When the convex portion 30 and the edge of the engagement hole 32 come into contact with each other at the contact 33 on the side close to the bent portion 31, the frictional force when the convex portion 30 is about to move is improved. As a result, the position of the pressing spring 26 is not easily displaced, and the bent portion 31 of the pressing spring 26 is difficult to protrude in the direction of the optical disk 12.

  Note that the shape of the engagement hole 32 is not limited as long as the edge of the engagement hole 32 is in contact with the convex portion 30.

(Example 2)
A second embodiment of the present invention will be described with reference to FIG. The second embodiment is different from the first embodiment in the shape of the engagement hole 32. The same configurations as those of the first embodiment are denoted by the same reference numerals as those of the first embodiment, and the descriptions of the first embodiment are used.

  In this embodiment, the engagement hole 32 is a perfect circle. In this case, the edge part of the engagement hole 32 and the convex part 30 are in line contact (contact with the line 36). The radius M of the engagement hole 32 is the same as the radius of the cross section of the protrusion 30 at the contact portion between the protrusion 30 and the edge of the engagement hole 32.

The shape of the engagement hole 32 is not limited as long as the edge of the engagement hole 32 is in contact with the projection 30, but the projection 30 and the edge of the engagement hole 32 are in contact with the side where the optical disk 12 is present. The area as large as possible is preferable because the frictional force is improved. In the second embodiment, the cross section of the convex portion 30 is a perfect circle, and the shape of the engagement hole 32 is also a perfect circle. Therefore, the contact portion is in line contact and the frictional force is further improved as compared with the first embodiment.
(Example 3)
A third embodiment of the present invention will be described with reference to FIGS. The third embodiment is different from the first embodiment in the convex portion 30. The same configurations as those of the first embodiment are denoted by the same reference numerals as those of the first embodiment, and the descriptions of the first embodiment are used.

  In this embodiment, the convex portion 30 is point-contacted with the edge of the engagement hole 32 only in the direction of the optical disk 12 (contacted by the contact point 37). Similar to the first embodiment, also in the third embodiment, the frictional force when the pressing spring protrusion 3 moves is improved, and the pressing spring 26 can be made difficult to protrude in the direction of the optical disk 12.

Moreover, the convex part 30 may be conical as shown in FIG. Moreover, the cross section of the convex part 30 should just be circular. The circular shape may be an elliptical shape as well as a perfect circular shape. However, in order to smoothly rotate the laser unit 24 for adjusting the grating, the cross section of the convex portion 30 is preferably a true circular shape.
Example 4
A fourth embodiment of the present invention will be described with reference to FIG. The fourth embodiment is different from the first embodiment in the shape of the bent portion 31 of the convex portion 30. The same configurations as those of the first embodiment are denoted by the same reference numerals as those of the first embodiment, and the descriptions of the first embodiment are used.

  In this embodiment, the bent portion 31 is formed with a predetermined radius of curvature. When the bent portion 31 is formed at a right angle, if the convex portion 30 is displaced from the engagement hole 32, it protrudes by N as shown in FIG. When the bent portion 31 is curved with a predetermined radius of curvature as shown in FIG. 13, even if the convex portion 30 is displaced from the engagement hole 32 as shown in FIG. It can be made smaller than the protruding amount N when the bent portion 31 is formed at a right angle.

  16 and 17 show graphs of experimental results in Examples 1 and 4.

  FIG. 16 is a graph showing the relationship between the radius Kmm of the cross section of the convex portion 30 and the torque g · mm when the adjustment pin is rotated. In order to prevent the position of the laser unit 24 from moving from the position at the time of grating adjustment, a torque of 550 g · mm or more is required.

  The conventional optical pickup uses a holding spring 53 having elasticity that can generate a torque of 550 g · mm, and makes the convex portion 57 point-contact with the shield case 56. Even if the radius of the convex portion 57 was changed, the contact point was not changed, and the torque did not change as shown in the graph 70.

  On the other hand, in Example 1 and Example 4 of the present invention, when the radius K described with reference to FIG. 8 is increased, the distance between the contact 33 and the contact 34 is increased. And the torque also increases.

A graph 71 shows the torque when the radius K is changed in the first and fourth embodiments of the present invention using the holding spring 53 having a torque of about 300 g · mm in the conventional optical pickup. In the first and fourth embodiments of the present invention, when the radius K is 0.65 mm, a torque of 550 g · mm can be generated even if the convex portion 30 having a torque of about 300 g · mm is used.

  As described above, in the first and fourth embodiments of the present invention, the holding spring 26 having a weaker elasticity than the conventional one can be used by adjusting the radius K.

  FIG. 17 shows the maximum protrusion amount (mm) of the bent portion 31 toward the optical disc 12 when the radius of curvature of the bent portion 31 is changed. A graph 72 is a graph of a conventional optical pickup, and uses a holding spring 53 capable of generating a torque of 550 g · mm.

  When the radius of curvature is zero, that is, when the bent portion 55 is a right angle, it protrudes by about 0.8 mm.

  If the radius of curvature is too large, it will come into contact with the optical bench 23 and can only be increased to a maximum of about 1 mm. When the curvature radius is increased, the maximum protrusion amount can be reduced. However, even if the curvature radius is about 1 mm which is the maximum value, the conventional optical pickup can reduce the maximum protrusion amount only to about 0.22 mm.

  The graph 73 shows that in Example 1 and Example 4 of the present invention, the pressing spring 26 having the torque of about 300 g · mm described with reference to FIG. 16 is used, and the radius K of the convex portion 30 is set to 0.65 mm and 550 g · mm. It is a graph at the time of enabling it to produce the torque of.

  The case where the radius of curvature is zero corresponds to the first embodiment, and at this time, the maximum protrusion amount can be set to about 0.6 mm, which is smaller than that of the conventional optical pickup. This is because, as described in the first embodiment, the contact between the convex portion 30 and the edge of the engagement hole 32 improves the frictional force when the convex portion 30 is about to move, and the position of the holding spring 26 is shifted. This is not only because it becomes difficult, but also because the elastic force of the holding spring 26 is weaker than that of the conventional optical pickup while generating the same torque as the conventional one, the convex portion 30 is less likely to be displaced from the engagement hole 32. .

  As described above, the maximum protrusion amount can be suppressed by providing the engagement hole 32 as in the first embodiment.

  Moreover, the maximum protrusion amount can be further reduced by increasing the radius of curvature of the bent portion 31 as in the fourth embodiment. In the graph 73, when the radius of curvature is about 1 mm at the maximum, the maximum protrusion amount can be reduced to about 0.05 mm, which is about 1/4, compared with about 0.22 mm in the related art.

  In many cases, the car audio device 1 has a predetermined thickness. In many cases, the number of optical disks 12 that can be simultaneously inserted into the optical disk apparatus 2 is also predetermined (for example, six).

  The car audio device 1 includes not only the optical disc device 2 but also a radio receiver 4 and a cassette tape recording / reproducing device 5. Therefore, the optical disk apparatus 2 needs to be as thin as possible while satisfying the predetermined number of optical disks 12 that can be simultaneously inserted. Here, considering the design size distribution of the optical disc device 2 and the optical pickup 3, it is desirable that the maximum protrusion amount of the bent portion 31 is 0.2 mm or less. In the present embodiment, it is preferable to set the curvature radius of the bent portion 31 to 0.48 mm or more as shown in the graph 73 because the maximum protrusion amount can be 0.2 mm or less.

  In addition, although the convex part 30 was described as hemispherical in Example 1, it should just be a shape which has a spherical surface.

  Moreover, in Example 1- Example 4, if the plate-shaped heat radiation part 25 can radiate the heat which the laser unit 24 emits, the material will not be limited. Further, the plate-like heat radiating portion 25 may be flat or may be a three-dimensional shape such as a box.

  Moreover, in Example 1- Example 4, although it described that the engagement hole 32 formed in the plate-shaped heat radiation part 25 was a through-hole, if the edge part of the convex part 30 and the engagement hole 32 can contact, it will penetrate It may be a hole that is not.

  In the first to fourth embodiments, the laser unit 24 oscillates laser light and reads data from the optical disk 12. However, the laser unit 24 oscillates laser light to write data to the optical disk 12. Also good.

  Moreover, in Example 1-4, although the convex part 30 was formed in the holding | suppressing spring 26 and it described that the engagement hole 32 which contacts the convex part 30 was formed in the plate-shaped thermal radiation part 25, it was described. An engagement hole 32 may be formed in 26, and a convex portion may be formed in the plate-like heat radiation portion 25.

  As described above, the optical pickup according to the present invention can provide a thin optical disc apparatus in which the bent portion of the pressing spring is difficult to protrude from the optical pickup and the distance between the optical disc and the optical pickup is reduced. The optical pickup according to the present invention is useful as an optical pickup used in, for example, a car audio apparatus incorporating an optical disk device.

1 is a perspective view of a car audio device incorporating an optical pickup according to Embodiment 1 of the present invention. 1 is a side view of an optical disc apparatus built in a car audio apparatus according to Embodiment 1 of the present invention. FIG. 2 is a top view of the optical disc apparatus viewed from the II position in FIG. The enlarged view of the optical pick-up in Example 1 of this invention 1 is a side view of an optical pickup according to a first embodiment of the present invention. 1 is an exploded perspective view of an optical pickup in Embodiment 1 of the present invention. Sectional drawing of the principal part of the optical pick-up in Example 1 of this invention Operational explanatory diagram of the optical pickup in Embodiment 1 of the present invention Operational explanatory diagram of an optical pickup in Embodiment 2 of the present invention Sectional drawing of the principal part of the optical pick-up in Example 3 of this invention Operational explanatory diagram of an optical pickup in Embodiment 3 of the present invention Sectional drawing of the principal part of the optical pick-up in Example 3 of this invention Sectional drawing of the principal part of the optical pick-up in Example 4 of this invention Comparison explanatory drawing of the optical pickup in Example 4 of this invention Operational explanatory diagram of an optical pickup in Embodiment 4 of the present invention The graph which shows the relationship between the radius of the cross section of the convex part in this invention, and a torque The graph which shows the relationship between the curvature radius and the maximum protrusion amount in this invention Sectional view of a conventional optical pickup Action diagram of conventional optical pickup

Explanation of symbols

2 Optical Disk Device 3 Optical Pickup 12 Optical Disk 14 Tray 23 Optical Stand 24 Laser Unit 25 Heat Dissipating Plate 26 Holding Spring 30 Protruding Part 31 Bending Part 32 Locking Hole

Claims (8)

A laser unit that oscillates laser light;
A heat dissipating part that is provided on the back surface of the laser unit in a direction opposite to a direction in which the laser light emitted by the laser unit is emitted,
An optical bench on which the laser unit is rotatably held;
One end is fixed to the optical bench, and the other free end includes a pressing spring pressed against the heat radiating portion,
An optical pickup, wherein a convex portion is formed on one of the pressing spring and the heat radiating portion, a hole is formed on the other, and the convex portion and an edge portion of the hole are in contact with each other. The said convex part makes point contact with the edge part of the said hole, and the width | variety of the edge part of the said hole point-contacted with the said convex part is larger than the width | variety of the said convex part. Optical pickup. The optical pickup according to claim 1, wherein the convex portion is spherical. The optical pickup according to claim 1, wherein the convex portion and the edge portion of the hole are in line contact. The optical pickup according to claim 4, wherein the convex portion is spherical and the hole is a true circle. The optical pickup according to claim 1, wherein the holding spring is formed in an L shape so as to follow the optical bench, and has a bent portion bent at a predetermined radius of curvature. The cross section of the convex portion at the contact portion with the edge of the hole is a circle having a radius of 0.65 mm or more, and the curvature radius of the bent portion of the pressing spring is 0.48 mm or more. Item 7. The optical pickup according to Item 6. An optical pickup according to any one of claims 1 to 7, and
A tray on which an optical disk is placed,
An optical disc apparatus, wherein the optical disc placed on the tray is irradiated with a laser beam oscillated by the laser unit, and at least one of data reading and writing is performed.