JP2011096304A - Optical pickup - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical pickup that reduces fall of a resin protector prepared in a lens holder. <P>SOLUTION: The optical pickup which reads information from a rotating optical disk mounted on a spindle mechanism or writes information in the optical disk, includes: an objective lens which condenses light from a light source to the optical disk; a lens holder having a recess formed on the side where the optical disk is mounted and holding the objective lens; and a protector made of resin materials and cured while being inserted in the recess. The recess has a part where the area of an opening is increased toward a lower surface side from a top surface side of the lens holder where the optical disk is mounted. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an optical pickup capable of reading information from an information recording medium such as an optical disk or recording information on the information recording medium. More specifically, the present invention relates to an apparatus for forming a protector made of a resin on an upper surface (side on which an optical disk is placed) of an optical pickup including an objective lens and a lens holder that holds the objective lens.

  As is well known, in an optical pickup in an optical head that optically reads or writes signals on a signal recording medium such as an optical disk, the lens holder on which the objective lens actuator is mounted is an elastic support member such as a support wire. Thus, focus control and tracking control of a light beam that is elastically supported so as to be displaceable with respect to the actuator frame and that is converged by the objective lens by driving the lens holder is performed on the signal recording medium. .

  By the way, in order to reduce the diameter of the light spot on the signal layer of the signal recording medium as the capacity of the signal recording medium increases, the objective lens for high density needs to have a large NA. On the other hand, in order to cope with the increase in the density of signal recording media, the moving parts of the actuator are being reduced in weight. Therefore, as the NA increases without increasing the diameter of the objective lens to be used, the distance (working distance) at which the lens holder can operate in the focus direction until the objective lens comes into contact with the signal recording medium is reduced. Yes.

  Therefore, the optical pickup is designed to prevent the objective lens and the signal recording medium from being damaged due to the objective lens colliding with the signal recording medium due to the displacement or impact of the objective lens in the optical axis direction when the focus servo is introduced. In addition, there is known one provided with a protector that protrudes from any part of the lens holder including the objective lens so as to approach the signal recording medium around the objective lens (see, for example, Patent Document 1).

  By the way, as a protector, as shown in Patent Document 1, the hardness is lower than that of a polycarbonate used as a material of a signal recording medium, for example, a transparent substrate that is a base material of DVD or CD, and other characteristics such as vibration proofing. Silicone rubber may be used. As this silicone rubber, there is a liquid agent type having curability, and it is conceivable to form this protector by applying this liquid agent type silicone rubber around the objective lens on the upper surface of the lens holder and curing the silicone rubber.

  Also, when a protector is formed by applying a curable liquid, the amount of liquid applied due to changes in the viscosity of the liquid during application, changes in the pressure of the dispenser that administers the liquid, or clogging of the needle tip from which the liquid is extracted Or the height of the protector formed due to various factors such as environmental changes such as the temperature and humidity at which the liquid is cured. A forming method for regulating the height of the protector by pressing is known. (For example, see Patent Document 2)

JP 2001-319355 A JP 2007-35083 A JP 2006-018978 A

  By the way, the above-mentioned Patent Documents 1 and 2 mention that the objective lens and the optical disk are prevented from being damaged by colliding with the optical disk. However, no mention is made of the fact that the resin protector provided on the lens holder comes off in collision with the optical disk.

  SUMMARY OF THE INVENTION In order to solve the above problems, an object of the present invention is to provide an optical pickup capable of reducing the dropping of a resin protector provided in a lens holder.

  The present invention is an optical pickup capable of reading information from an optical disk rotated while mounted on a spindle mechanism or writing information on the optical disk, and condenses light from a light source onto the optical disk. An objective lens, and a concave portion formed on the side on which the optical disk is placed, a lens holder for holding the objective lens, and a protector made of a resin material and cured in a state of being inserted into the concave portion. . And the said recessed part has a part from which the opening area becomes large toward the lower surface side from the upper surface side of the said lens holder which is the side in which the said optical disk is mounted.

  Note that Patent Document 2 does not mention the height restriction of the protector provided in the lens holder.

  Therefore, in the 2nd form of this invention, the said recessed part has a through-hole which penetrates at least another area | region further.

  In this way, after the protector that is liquid is inserted into the recess, when the protector is in a semi-cured state, the height of the protector is restricted by closing the through-hole with a regulating member separate from the lens holder. Can be easily done.

  According to the optical pickup of the present invention, even when the optical disk collides with the protector, the resin protector provided on the lens holder can be prevented from falling off.

The perspective view which shows an example of the optical pick-up with which the protector which concerns on this Embodiment was formed (A) Main part sectional drawing of the lens holder which concerns on this Embodiment, (b) Sectional drawing which formed the protector in the lens holder (A) Main part sectional drawing of the lens holder in other embodiment, (b) is sectional drawing which formed the protector in the lens holder (a) Main part sectional drawing of the lens holder in other embodiment, (b) is sectional drawing which formed the protector in the lens holder (a) Main part sectional drawing of the lens holder in other embodiment, (b) is sectional drawing which formed the protector in the lens holder (a) Main part sectional drawing of the lens holder in other embodiment, (b) is sectional drawing which formed the protector in the lens holder (a) Main part sectional drawing of the lens holder in other embodiment, (b) is sectional drawing which formed the protector in the lens holder (a) Main part sectional drawing of the lens holder in other embodiment, (b) is sectional drawing which formed the protector in the lens holder (a) Main part sectional drawing of the lens holder in other embodiment, (b) is sectional drawing which formed the protector in the lens holder Sectional view of a conventional optical pickup lens holder and protector Sectional view of a conventional optical pickup lens holder and protector

  The optical pickup of the present embodiment will be described with reference to the drawings.

  FIG. 1 is a perspective view showing a completed state of an example of an optical pickup for DVD and CD on which a protector is formed according to an embodiment of the present invention.

  An objective lens 7 is attached to the lens holder 1, and a focusing coil 8 that is wound so as to surround the entire side surface of the lens holder 1 and a tracking coil 9 that is disposed at four corners of the lens holder 1 are wound. It has been turned.

  One end of each of the four suspension wires 10 that support the lens holder 1 is fixed to the wiring board 12 that is fixed to the actuator frame 11, and the other end side of each of the suspension wires 10 faces the lens holder 1. Are fixed to the respective support portions protruding from the upper and lower centers of the two side surfaces.

  Accordingly, the lens holder 1 is elastically supported by the four suspension wires 10 so as to be displaceable in the focus direction and the tracking direction by the actuator frame 11. In this case, two suspension wires 10 are arranged on both sides of the lens holder 1, and are suspended in parallel with each other in the vertical direction and in the shape of a letter C in the horizontal direction.

  Then, on the tip of the other end side of each suspension wire 10 fixed to the lens holder 1, each projecting piece to which a predetermined terminal of each driving coil of the focusing coil 8 and the tracking coil 9 is entangled is integrated with the lens holder 1. The suspension wire 10 is soldered near the tip of the other end of each suspension wire 10, and one end of each suspension wire 10 is soldered to the land of the wiring board 12, thereby supplying the wiring board 12. The focus and tracking control signals are supplied to the drive coils via the suspension wires 10.

  In addition, the actuator frame 11 applies an effective magnetic field to the effective side of each drive coil in a state where the lens holder 1 is installed and supported at a predetermined position by four suspension wires 10 (the two below on both sides are not shown). A magnetic circuit is provided to generate. Therefore, by supplying a focus control signal to the focusing coil 8, the objective lens 7 is driven in the focus direction via the lens holder 1 in accordance with the focus control signal, and tracking is performed on each tracking coil 9. By supplying a control signal, the objective lens 7 is driven in the tracking direction via the lens holder 1 in accordance with the tracking control signal.

  The above is the configuration of the optical pickup in this embodiment. Among these, the roles of the lens holder 1 and the protector 4 which are characteristic portions of the embodiment will be described in detail.

  On the upper surface of the lens installation portion where the objective lens 7 of the lens holder 1 is installed, a protector is provided around each of the objective lenses 7 serving as the four corners of the lens installation portion (there may be four corners or more depending on the structure). 4 protrudes in a dome shape. Each protector 4 protrudes from the other part of the actuator movable part (the upper surface of the rim part of the objective lens 7) to the opposite disk side, and each protector 4 is a part where the actuator movable part is in contact with the disk. .

  Here, each of the protectors 4 is made of silicone rubber or the like, and has a lower hardness than the polycarbonate of the disk substrate. The protector 4 is displaced by the displacement or impact of the objective lens 7 in the optical axis direction when the focus servo is introduced. Even if the disk collides with the disk, the disk is prevented from being damaged.

  Further, the protector 4 has a height in consideration of the deformation so that the objective lens 7 is prevented from coming into contact with the disc even if the protector 4 is deformed by coming into contact with the disc. Is also prevented.

  If the protector 4 is made of silicone rubber, it can be expected that the higher-order resonance characteristics of the actuator will be effective due to the vibration-proofing of the silicone rubber.

Next, the shape of the lens holder 1, which is important for preventing the protectors 4 from falling off, will be described in each embodiment while comparing the structure of the conventional example and this embodiment with cross-sectional views. Further, the shape of the lens holder described in each embodiment incorporates a function that can easily regulate the height of the protector as described in Patent Document 2, in addition to preventing the protector from falling off.
(Embodiment 1)
2 and 3 are examples of cross-sectional views of the lens holder and the protector of the optical pickup according to the first embodiment. 10 and 11 are examples of cross-sectional views of a lens holder and a protector of a conventional optical pickup (see Patent Document 3).

  When the protector 4 is formed by pouring a curable liquid agent into the concave portion 2 of the lens holder 1 and curing the liquid agent on the upper surface side of the lens holder 1 in a state where the liquid agent is retained by viscosity, the protector 4 is formed as shown in FIGS. In such a conventional lens holder structure, the concave portion 2 has a structure in consideration of a draft angle of a general mold in which the opening area becomes the same or narrows from the upper surface to the lower surface, and the protector 4 is randomly inclined left and right. When the impact is received, the protector 4 becomes like a cradle due to the structure of the recess 2, and the force cannot be absorbed in the recess and falls out of the lens holder 1.

  However, in the invention structure as shown in FIGS. 2 and 3, the structure for removing the mold is devised, for example, the recess 2 is partially expanded from the upper surface side to the lower surface side so as not to hinder molding. Therefore, the force that the protector tries to fall off in the concave portion is dispersed even in the case of a random impact or an intermittent impact that is oblique to the protector 4, so that the protector 4 does not become a cradle, and the lens holder No drop off from 1. It can be said that it is a very useful means that the strength of the protector itself can be prevented from falling off with such a simple structure.

  The invention structure of the concave portion 2 may be a method using a draft angle of the mold, but a method of pulling the lens holder 1 at an angle by screwing or the like and a method of cutting toward the lower surface side. Is also possible. In addition, when the screw is removed, the protector 4 has a very high strength compared to the conventional structure even if the recess 2 has the same or narrower opening area from the upper surface to the lower surface as in the conventional structure. This is because when screw unscrewing is used, there is a merit that the liquid agent enters the screw thread when the liquid agent is poured, and the strength of the protector 4 itself is increased.

4 is an example of a cross-sectional view of the lens holder and the protector to which the partial through hole of the optical pickup according to the first embodiment is added. FIG. 4 is a structure obtained by further evolving FIG. 2 and FIG. One or a plurality of partial through holes 3 are provided in the concave portion 2 of the lens holder 1. This partial through-hole 3 is used for forming a protector 4 by pouring a liquid agent, such as a temperature / humidity environment, an environment in which the liquid agent is poured, etc. ) Can be said to be a very effective means for preventing the strength of the protector 4 from being insufficient and the protector 4 from falling off when bubbles are formed in the liquid agent.
(Embodiment 2)
5 and 6 are examples of cross-sectional views of the lens holder, the protrusion, and the protector of the optical pickup according to the second embodiment. 10 and 11 are sectional views of a lens holder and a protector of a conventional optical pickup.

  When the protector 4 is formed by pouring a curable liquid agent into the concave portion 2 of the lens holder 1 and curing the liquid agent on the upper surface side of the lens holder 1 in a state where the liquid agent is retained by viscosity, the protector 4 is formed as shown in FIGS. In such a conventional lens holder structure, the concave portion 2 has a structure in consideration of a draft angle of a general mold in which the opening area becomes the same or narrows from the upper surface to the lower surface, and the protector 4 is randomly inclined left and right. When the impact is received, the protector 4 becomes like a cradle due to the structure of the recess 2, and the force cannot be absorbed in the recess and falls out of the lens holder 1.

  However, in the invention structure as shown in FIGS. 5 and 6, by providing one or a plurality of protrusions 5 in the recess 2, the surface area in contact with the liquid agent is increased when the liquid agent is poured. For random impacts, intermittent impacts, etc., there is no cradle-like state, and the strength is greatly increased. The material of the protrusion 5 may be integrally molded with the same material as that of the lens holder 1, but another material may be bonded to the lens holder 1. Further, the height h1 of the protrusion 5 should not be higher than the height h2 from the lens holder of the protector 4. This is because it is important that damage to the disk is prevented by the protector 4 colliding with the disk.

  Further, in addition to the protrusion 5, if the structure for removing the mold of the concave portion 2 is devised, for example, a structure in which the opening area is partially expanded from the upper surface side to the lower surface side so as not to hinder the molding, This is also a very useful means because the force is further dispersed in the recesses against left and right oblique random impacts and intermittent impacts, and the protector 4 does not become a cradle.

  The invention structure of the concave portion 2 may be a method using a draft angle of the mold, but a method of pulling the lens holder 1 at an angle by screwing or the like and a method of cutting toward the lower surface side. Is also possible. In addition, when the screw is removed, the protector 4 has a very high strength compared to the conventional structure even if the recess 2 has the same or narrower opening area from the upper surface to the lower surface as in the conventional structure. This is because when screw unscrewing is used, there is a merit that the liquid agent enters the screw thread when the liquid agent is poured, and the strength of the protector 4 itself is increased.

FIG. 7 is a cross-sectional view of a lens holder, a protrusion, and a protector to which a partial through hole of the optical pickup in the second embodiment is added. FIG. 7 has a structure obtained by further evolving FIGS. 5 and 6, and the concave portion 2 of the lens holder 1 is provided with one or a plurality of partial through holes 3. This partial through-hole 3 is used for forming a protector 4 by pouring a liquid agent, such as a temperature / humidity environment, an environment in which the liquid agent is poured, etc. ) Can be said to be a very effective means for preventing the strength of the protector 4 from being insufficient and the protector 4 from falling off when bubbles are formed in the liquid agent.
(Embodiment 3)
8 and 9 are cross-sectional views of the lens holder and the protector of the optical pickup according to the third embodiment. 10 and 11 are examples of cross-sectional views of a lens holder and a protector of a conventional optical pickup.

  When the protector 4 is formed by pouring a curable liquid agent into the concave portion 2 of the lens holder 1 and curing the liquid agent on the upper surface side of the lens holder 1 in a state where the liquid agent is retained by viscosity, the protector 4 is formed as shown in FIGS. In such a conventional lens holder structure, the concave portion 2 has a structure in consideration of a draft angle of a general mold in which the opening area becomes the same or narrows from the upper surface to the lower surface, and the protector 4 is randomly inclined left and right. When the impact is received, the protector 4 becomes like a cradle due to the structure of the recess 2, and the force cannot be absorbed in the recess and falls out of the lens holder 1.

  However, since the invention structure as shown in FIGS. 8 and 9 has a through-hole shape in which a part of the opening area is enlarged from the upper surface side to the lower surface side, the left and right oblique random impacts on the protector 4 and intermittent The force is dispersed in the through-hole 6 even with an impact or the like, and the protector 4 does not become like a cradle and does not fall off from the lens holder 1. It can be said that the strength of the protector itself with such a simple structure is very useful. Also, because of the through-hole structure, when the protector 4 is formed by pouring the liquid agent, the temperature / humidity environment, the environment in which the liquid agent is poured, etc. Etc.), when bubbles are formed in the liquid agent, it can be said to be a very effective means for preventing insufficient strength of the protector 4 due to the bubbles and preventing the protector 4 from falling off.

  Here, the structure of the through hole 6 is different from the structure of the concave portion 2 as in the prior art, and has an advantage that the lens holder 1 can be removed from both the upper and lower surfaces when the mold is removed. In addition, since the structure in which the opening area is widened toward the lower surface is also a through-hole structure, the draft angle of the mold can be easily used.

  The invention structure of the above-described through-hole 6 may be a method using the draft angle of the mold, but a method of pulling the lens holder 1 toward the upper and lower surfaces side with an angle by screwing or the like is also conceivable. Further, when screwing or the like, the protector 4 has a very high strength compared to the conventional structure even if the through hole 6 has a structure in which the opening area is the same or narrower from the upper surface to the lower surface as in the conventional structure. This is because when screw unscrewing is used, there is a merit that the liquid agent enters the screw thread when the liquid agent is poured, and the strength of the protector 4 itself is increased.

  In addition, since the invention example has a through-hole structure, compared to the conventional example, when forming the protector 4 by pouring the liquid agent, the temperature / humidity environment, the environment in which the liquid agent is poured, etc. (for example, pressure change of the dispenser, Depending on the amount of application due to clogging of the needle tip or the like, there is a possibility that bubbles may be formed. In addition, it can be said that the liquid agent can be poured from either the upper surface side or the lower surface side of the lens holder 1.

  The optical pickup according to the present invention can prevent the protector from falling off by the simple structure of the lens holder and can easily regulate the height of the protector in the method of forming the protector for applying and injecting the liquid agent. It is useful for applications such as optical pickups such as BD, DVD, and CD that have improved protection performance for protecting the lens from collision.

DESCRIPTION OF SYMBOLS 1 Lens holder 2 Concave part 3 Partial through-hole 4 Protector 5 Protrusion 6 Through-hole 7 Objective lens 8 Focusing coil 9 Tracking coil 10 Suspension wire 11 Actuator frame 12 Wiring board A Objective lens side (upper surface side)
B Bottom side (lower side)

Claims (4)

An optical pickup capable of reading information from an optical disk rotated in a state of being mounted on a spindle mechanism or writing information on the optical disk,
An objective lens for condensing the light from the light source onto the optical disc;
A concave portion is formed on the side on which the optical disk is placed, and a lens holder for holding the objective lens;
A protector made of a resin material and cured in a state of being inserted into the recess;
With
The concave portion has a portion whose opening area increases from the upper surface side to the lower surface side of the lens holder on which the optical disk is placed.
Optical pickup The protector is provided closer to the optical disk placed on the spindle mechanism than the objective lens.
The optical pickup according to claim 1. The recess has a through-hole penetrating at least another region.
The optical pickup according to claim 1. The recess has a protrusion protruding from the upper surface of the lens holder.
The optical pickup according to claim 1.

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