JP4717074B2 - Collision prevention mechanism and manufacturing method thereof - Google Patents

Description

  The present invention relates to a technical field of a collision prevention mechanism provided in an optical pickup in an optical disc system and a manufacturing method thereof.

  In recent years, an optical disk system is widely used as means for recording and reproducing data such as video and audio. Optical disc systems are required to have higher density and miniaturization. In order to increase the density and miniaturization of the optical disk system, a so-called working distance (WD) from the lens surface of the objective lens provided in the optical pickup that irradiates the optical disk to the surface of the optical disk is set. It is necessary to reduce the size, and the possibility of the objective lens colliding with the optical disk surface increases with this reduction. In particular, when the focus servo is lost, there is a high possibility that the objective lens will collide with the optical disk surface.

  Various proposals have been made for preventing such collision between the objective lens and the optical disk surface. For example, Patent Document 1 proposes a technique for forming a film in which an objective lens and an objective lens holding member are mixed with polyurethane particles and fluororesin powder based on urethane resin. In patent document 2, the present applicant proposes a technique for forming a buffer layer made of an ultraviolet curable resin on the outer edge or outside of the objective lens from the periphery of the lens effective surface of the objective lens. Patent Document 3 proposes a technique of forming a coating layer made of a material that is softer and more slidable than an optical disk on the disk-side end surface of the lens holder. Patent Document 4 proposes a technique of providing a synthetic resin stopper or a stopper integrated with the lens holder by two-color molding at the corner of the lens holder.

JP 2003-242703 A JP 2002-237071 A JP 2002-222535 A JP 2002-197704 A

  However, in the techniques according to Patent Documents 1 to 4, since the anti-collision coating, the buffer layer, and the like are formed relatively thick on the holding portion of the objective lens so as to be higher than the upper surface of the objective lens, There is a technical problem that it is difficult to control a minute thickness of a layer or the like. In particular, in order to realize a very small working distance, there is a technical problem that the thickness of the coating film, the buffer layer, and the like must be managed with high accuracy during manufacturing.

  The present invention has been made in view of the above-described problems, for example, and a collision prevention mechanism capable of reducing the working distance between the objective lens and the optical disk while reliably preventing the collision between the objective lens and the optical disk, and a method for manufacturing the same. It is an issue to provide.

(Collision prevention mechanism)
In order to solve the above problems, a collision prevention mechanism of the present invention is a collision prevention mechanism for preventing a collision between an objective lens mounted on an optical pickup in an optical disc system and the surface of the optical disc, and is provided on the optical pickup. A predetermined bottom portion of the bottom surface portion with a predetermined width as seen in a plan view on the bottom surface portion and protruding in a direction facing the optical disc on the bottom surface portion. A base having at least one protrusion provided so as to surround or adjoin the one part over the predetermined width; and on at least the protrusion and the one part of the base comprises Ru and collision prevention layer name is coated soft elastic member than the material of the surface of the optical disk, versus the optical disc of the protrusions of the anti-collision layer The surface of the first portion located on the leading end surface facing the optical disc is farther from the bottom surface than the surface of the second portion located on the one portion of the anti-collision layer facing the optical disc. Is formed .

  The collision prevention mechanism of the present invention is provided in an optical pickup equipped with an objective lens in an optical disc system. Specifically, the bottom surface portion is provided on the optical pickup, and the projecting portion protrudes from the optical disk.

  According to the collision prevention mechanism of the present invention, during operation of the optical disk system, even when the objective lens comes close to the surface of the optical disk, for example, when the focus servo is removed, In addition, since the soft collision prevention layer collides with the optical disk, it is possible to prevent the optical disk from being damaged by the collision of the objective lens.

  More specifically, the anti-collision mechanism of the present invention includes a base and an anti-collision layer. The base has a bottom surface portion and a protruding portion protruding on the bottom surface portion in a direction facing the optical disk. The bottom surface portion is provided on the optical pickup or integrally with the optical pickup. The projecting portion, when viewed in plan on the bottom surface portion, surrounds at least one portion of the bottom surface portion with a predetermined width, or is adjacent to the at least one portion over the predetermined width. Is provided. In other words, the protrusion has a shape such as a cylindrical shape, an elliptical cylindrical shape, or a polygonal cylindrical shape. Or it has shapes, such as circular, a rectangle, and a polygon, seeing planarly from a bottom face part. An anti-collision layer made of an elastic member softer than the optical disk is formed so as to cover the protruding portion.

  Particularly in the collision prevention mechanism of the present invention, the collision prevention layer is formed by applying an elastic member softer than the optical disk to the protruding portion. Furthermore, the surface of the anti-collision layer opposite to the surface facing the protrusion of the first portion located on the tip of the protrusion is on one part of the anti-collision layer surrounded by the protrusion. The second portion is positioned farther from the bottom surface than the surface opposite to the surface facing the bottom surface. That is, the collision prevention layer is formed, for example, by applying a liquid elastic member, such as silicon rubber, which is softer than, for example, polycarbonate resin used as a material for the surface of the optical disc so as to cover the protruding portion. The At this time, the liquid elastic member applied to one part of the bottom surface portion surrounding or adjacent to the protruding portion has a protruding portion due to the relationship between the surface tension, viscosity, liquid repellency, etc. and the height of the protruding portion. It is not formed so as to be higher than the height. Typically, the applied liquid elastic member immediately covers the entire protrusion including one part of the bottom portion immediately after being applied, but as time passes, the tip of the protrusion To the bottom surface (that is, one portion surrounded by the protrusion or the outside of the protrusion). Eventually, a first portion of the anti-collision layer that is thinner than that immediately after coating is formed at the tip of the protrusion having a predetermined width, and the first portion of the anti-collision layer is formed on one portion. Two parts are formed. The thickness of the anti-collision layer can be adjusted, for example, by changing the amount and type (ie, viscosity, thixo ratio, etc.) of the elastic member to be applied. Further, the thickness of the anti-collision layer can be adjusted by changing the width of the tip of the protrusion, the material of the protrusion, and the like. For example, if the width of the tip of the protrusion is reduced, the thickness of the anti-collision layer can be reduced. Conversely, if the width of the tip of the protrusion is increased, the thickness of the anti-collision layer is increased. be able to. Therefore, a relatively thin anti-collision layer can be easily and highly accurately formed by narrowing the width of the tip of the protrusion and applying a soft elastic member thereon. In other words, the anti-collision layer can be formed without having to manage the amount of the soft elastic member to be applied with high accuracy. Therefore, the surface of the first part of the collision prevention layer that faces the optical disk is positioned at a position where the objective lens (more precisely, the part of the objective lens that faces the optical disk that is closest to the optical disk) is closest to the optical disk by focusing. In the optical disc system, for example, the working distance between the objective lens and the optical disc can be shortened by forming the anti-collision layer with high accuracy so as to be close to the optical disc.

  In addition, the surface opposite to the surface which faces the protrusion part of the 1st part of a collision prevention layer is made into 2nd of a collision prevention layer by making the protrusion height from the bottom face part of a protrusion part comparatively high. It can be made to leave | separate from a bottom face part rather than the surface on the opposite side to the surface which faces the bottom face part of a part.

  In one aspect of the collision preventing mechanism of the present invention, the elastic member includes at least an ultraviolet curable adhesive resin.

  According to this aspect, the anti-collision layer can be formed by irradiating ultraviolet rays after applying the ultraviolet curable adhesive resin, which is liquid at the time of application, to the protrusions.

  In addition, an elastic member may be formed from resin, such as photocurable resins other than an ultraviolet-ray, thermosetting resin other than this.

In another aspect of the collision preventing mechanism of the present invention, the protruding portion is provided so as to surround the one portion with a predetermined width when viewed in plan on the bottom surface portion. The area of the surface facing the bottom surface portion is larger than the area of the tip surface .

  According to this aspect, when applied, the elastic member that has flowed out from the tip portion can be easily stored in the portion surrounded by the protruding portion. Therefore, it is possible to form the collision prevention layer on the tip portion of the protruding portion with a desired thickness and to prevent the elastic member from flowing out to the outside of the protruding portion.

  In another aspect of the collision preventing mechanism of the present invention, the protruding portion is formed in a cylindrical shape, an elliptical cylindrical shape, or a polygonal cylindrical shape.

  According to this aspect, when applied, the elastic member that has flowed out from the tip can be stored inside the cylinder. Therefore, it is possible to form the collision prevention layer on the tip portion of the protruding portion with a desired thickness and to prevent the elastic member from flowing out to the outside of the protruding portion.

(Method for manufacturing collision prevention mechanism)
In order to solve the above problems, a method for manufacturing a collision prevention mechanism according to the present invention is a collision prevention mechanism for preventing a collision between an objective lens mounted on an optical pickup in an optical disk system and the surface of an optical disk. A collision prevention mechanism for producing a collision prevention mechanism provided with a collision prevention layer provided on the optical pickup, the bottom surface provided on the optical pickup, and the direction facing the optical disc on the bottom in predetermined predetermined width one portion of said optical width of the tip surface facing the disk it has been adjusted to correspond to the thickness to be formed of the anti-collision layer and the bottom surface portion with projecting Forming the base with at least one protrusion so as to surround or be adjacent to the portion over the predetermined width;
An elastic member softer than the material of the surface of the optical disk is provided on at least the protrusion and the one part on the base, and a surface of the first part located on the tip surface is opposed to the optical disk . And a step of applying the second portion positioned on the portion so as to be farther from the bottom surface than the surface facing the optical disc .

  According to the manufacturing method of the collision prevention mechanism of the present invention, the above-described collision prevention mechanism of the present invention can be manufactured. Here, in particular, a relatively thin collision prevention layer can be formed easily and with high accuracy by forming a narrow width at the tip of the protrusion and applying a soft elastic member thereon. Therefore, the surface of the first part of the collision prevention layer that faces the optical disk is positioned at a position where the objective lens (more precisely, the part of the objective lens that faces the optical disk that is closest to the optical disk) is closest to the optical disk by focusing. In the optical disc system, for example, the working distance between the objective lens and the optical disc can be shortened by forming the anti-collision layer with high accuracy so as to be close to the optical disc.

  The operation and other advantages of the present invention will become apparent from the embodiments described below.

  As described above in detail, the collision prevention mechanism of the present invention includes a bottom surface portion, a base having a protruding portion on the bottom surface portion, and a collision prevention layer formed by applying an elastic member softer than the base. A relatively thin anti-collision layer can be formed easily and with high accuracy. That is, the collision prevention layer can be formed without having to manage the amount of the elastic member to be applied with high accuracy. The manufacturing method of the collision prevention mechanism of the present invention includes a step of forming a bottom surface portion and a base having a protruding portion on the bottom surface portion, and a step of applying an elastic member softer than the base to at least the protruding portion on the base. Therefore, the collision prevention mechanism of the present invention can be manufactured.

It is a perspective view which shows the structure of an optical pick-up. It is a perspective view which expands and shows the actuator of FIG. It is a top view which expands and shows the dotted-line circle C1 part of FIG. It is sectional drawing in the AA 'line of FIG. It is a flowchart which shows the manufacturing process of the collision prevention mechanism which concerns on 1st Example. It is explanatory drawing which shows the time change of the collision prevention layer in the manufacturing process of the collision prevention mechanism which concerns on 1st Example. It is a perspective view which shows the collision prevention mechanism which concerns on 2nd Example. It is sectional drawing in the line along the X direction of the collision prevention mechanism in FIG. It is explanatory drawing which shows the simulation protrusion part which simulates the protrusion part of the collision prevention mechanism which concerns on 1st and 2nd Example. It is a figure which shows the content of the experiment using the simulation protrusion part.

Explanation of symbols

21 Collision prevention mechanism 22 Projection part 23 Bottom face part 24 Base 25 Collision prevention layer 25a 1st part 25b 2nd part

  Hereinafter, the best mode for carrying out the present invention will be described for each embodiment in order with reference to the drawings.

(First embodiment)
First, an optical pickup provided with a collision prevention mechanism according to a first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a perspective view showing the configuration of the optical pickup.

  In FIG. 1, an optical pickup 10 includes a laser diode 1, a collimator lens 2, half mirrors 3 and 4, a mirror 5, a multi lens 6, a light receiving element 7, an objective lens 8, an actuator 9, and a casing 11.

  The laser diode 1 emits a light beam b1 having a specific wavelength and makes the light beam b1 incident on the collimator lens 2. The collimator lens 2 emits a light beam b2 (first light beam) in which the light beam b1 is converted into parallel light. The light beam b <b> 2 passes through the half mirrors 3 and 4, enters the mirror 5, and enters the objective lens 8.

  The objective lens 8 is fixed on an objective lens holding portion 9h1 that constitutes a part of the actuator 9, condenses the light beam b2, and emits a light beam b2c (second light beam) that is a spot light. To do. A support portion 9h2 constituting a part of the actuator 9 is fixedly arranged on the casing 11 so as to be movable, and the objective lens holding portion 9h2 or the objective lens 8 is moved in the radial direction of the optical disc D as indicated by arrows 9a and 9b. It can be moved in the focusing direction (ie, the direction perpendicular to the optical disc). This makes it possible to perform so-called tracking servo and focusing servo in which the spot of the light beam b2c emitted from the objective lens 8 is arranged on the target track of the optical disc D that is a recording medium. The optical pickup 10 configured in this way is configured to be movable in the radial direction of the optical disc D together with the casing 11 by a slider motor (not shown).

  The light beam b2c emitted from the objective lens 8 is applied to the information recording surface of the optical disc D. At this time, the reflected light b3 reflected by the optical disc D enters the objective lens 8. The reflected light b <b> 3 is reflected by the mirror 5, passes through the half mirror 4, and enters the multilens 6. The reflected light b <b> 3 is collected by the multi lens 6 and received by the light receiving element 7. Thereby, the information recorded on the optical disc D can be read.

  In the present embodiment, in particular, the collision prevention mechanism 21 is provided in the objective lens holding portion 9h1 constituting a part of the optical pickup 10. Therefore, during the operation of the optical disk system, even when the objective lens 8 approaches the surface of the optical disk D due to, for example, the focus servo being removed, the collision prevention mechanism 21 causes the objective lens 8 to collide with the optical disk D. Can be prevented from being damaged.

  Next, the collision prevention mechanism according to the first embodiment of the present invention will be described in detail with reference to FIGS. FIG. 2 is an enlarged perspective view showing the actuator shown in FIG. 3 is an enlarged plan view showing a dotted circle C1 portion of FIG. 4 is a cross-sectional view taken along line AA ′ of FIG.

  As shown in FIG. 2, the actuator 9 includes an objective lens holding portion 9h1, a suspension 9s, and a support portion 9h2.

  The objective lens holding portion 9h1 is made of, for example, synthetic resin, and has an opening portion 8a for holding the objective lens 8 (see FIG. 1). The objective lens 8 is held in the opening 8a. Further, in this embodiment, a collision prevention mechanism 21 to be described later is provided on the surface of the objective lens holding portion 9h1 on the side facing the optical disc D.

  The suspension 9s is made of, for example, an elastic wire, and connects between the objective lens holding portion 9h1 and the support portion 9h2.

  The support portion 9h2 is made of, for example, a synthetic resin, and is fixedly disposed on the casing 11 as described above.

  As shown in FIGS. 2 to 4, the collision prevention mechanism 21 is provided on the objective lens holding portion 9h1 so as to protrude with respect to the optical disc D (see FIG. 1).

  More specifically, as shown in FIG. 4, the collision prevention mechanism 21 includes a base 24 and a collision prevention layer 25.

  The base 24 has a bottom surface part 23 and a protruding part 22.

  The bottom surface portion 23 is constituted by a part of the objective lens holding portion 9h1, and is made of, for example, a synthetic resin. The protruding portion 22 is formed integrally with the bottom surface portion 23. The protruding portion 22 may be formed by attaching a component made of the same or different material as the bottom surface portion 23.

  As shown in FIGS. 3 and 4, the protrusion 22 is adjacent to the portion 23a over the width W1 so as to surround the portion 23a of the bottom portion 23 with a width W1 when viewed in plan on the bottom portion 23. It is provided as follows. In other words, the protruding portion 22 has a polygonal cylindrical shape, that is, as shown in FIG. 3, the protruding portion 22 has a polygonal shape when viewed in plan from the bottom surface portion 23. In addition, the protrusion part 22 may have shapes, such as cylindrical shape and elliptic cylinder shape. The portion 23a is an example of the “one portion” according to the present invention. As will be described later, the width W1 is determined in advance according to the thickness of the collision prevention layer 25 at the tip of the protrusion 22.

  The collision prevention layer 25 is made of silicon rubber that is softer than the optical disc D, and is formed so as to cover the protruding portion 22.

  In FIG. 4, in particular, in the collision prevention mechanism 21 according to the present embodiment, the collision prevention layer 25 is formed by applying silicon rubber softer than the optical disk D to the protrusion 22. Furthermore, a surface 25as of the first portion 25a located on the tip of the protrusion 22 in the anti-collision layer 25 opposite to the surface facing the protrusion 22 is surrounded by the protrusion 22 in the anti-collision layer 25. The second portion 25b located on the portion 23a is further away from the bottom surface portion 23 than the surface 25bs opposite to the surface facing the bottom surface portion 23. More specifically, the collision prevention layer 25 is formed by applying liquid silicon rubber softer than, for example, polycarbonate resin used as a material for the surface of the optical disc D so as to cover the protruding portion 22. ing. At this time, the liquid silicone rubber applied to the portion surrounding the protruding portion 22 or the portion 23a adjacent thereto is from the relationship between the surface tension, viscosity, liquid repellency, etc. and the height H of the protruding portion 22, Finally, it is not formed so as to rise above the protrusion 22. In other words, the applied liquid silicone rubber covers the entire protruding portion 22 including the portion 23a of the bottom surface portion 23 immediately after being applied. However, as time passes, the applied liquid silicon rubber starts from the tip portion of the protruding portion 22. It flows out to the bottom face part 23 (namely, the part 23a enclosed by the protrusion part 22 or the outer side of the protrusion part 22). Finally, the first portion 25a of the thin-film collision prevention layer 25 which is thinner than that immediately after the application is formed at the tip portion having the width W1 of the protruding portion 22, and the first portion 25a of the collision prevention layer 25 is formed on the portion 23a. Two portions 25b are formed. The thickness of the anti-collision layer 25 can be adjusted, for example, by changing the amount and type of liquid silicone rubber to be applied (ie, viscosity, thixo ratio, etc.). Further, the thickness of the collision preventing layer 25 can be adjusted by changing the width W1 of the tip of the protruding portion 22, the material of the protruding portion 22, and the like. For example, if the width W1 of the tip of the protrusion 22 is reduced, the thickness of the first portion 25a of the collision prevention layer 25 can be reduced, and conversely if the width W1 of the tip of the protrusion 22 is increased. The thickness of the first portion 25a can be increased. Therefore, the comparatively thin collision prevention layer 25 can be formed easily and with high accuracy by forming the width W1 of the tip end portion of the protruding portion 22 narrowly and applying soft liquid silicon rubber thereon. In other words, the collision prevention layer 25 can be formed without having to manage the amount of liquid silicon rubber applied with high accuracy. Therefore, the surface 25as of the first portion 25a of the collision prevention layer 25 facing the optical disc D is the objective lens 8 (more precisely, the portion of the surface facing the optical disc D of the objective lens 8 closest to the optical disc D). In the optical disc system, the working distance between the objective lens 8 and the optical disc D can be shortened by forming the anti-collision layer 25 with high accuracy so as to be closer to the optical disc D than the position 8s closest to the optical disc D by focusing. Is possible.

  Next, a manufacturing method of the collision preventing mechanism for manufacturing the above-described collision preventing mechanism according to the first embodiment of the present invention will be described with reference to FIGS. 2 and 4 to 6. FIG. 5 is a flowchart showing a manufacturing process of the collision prevention mechanism, and FIG. 6 is an explanatory diagram showing a temporal change of the collision prevention layer in the manufacturing process of the collision prevention mechanism.

  As shown in FIG. 5, according to the manufacturing method of the collision preventing mechanism according to the present embodiment, first, the base 24 is formed by the base forming process (step S1). At this time, as shown in FIG. 4, the bottom surface 23 of the base is formed of, for example, a synthetic resin or the like as a part of the objective lens holding portion 9h1 (see FIG. 2) on the side facing the optical disc D. Further, on the bottom surface portion 23, the protruding portion 22 protrudes in the direction of the optical disc D and surrounds the portion 23a of the bottom surface portion 23 with the width W1 of the tip portion (or is adjacent to the portion 23a over the width W1. Formed). That is, the protrusion 22 is formed to have a polygonal cylindrical shape. In addition, the protrusion part 22 may have shapes, such as cylindrical shape and elliptic cylinder shape. Further, the protruding portion 22 may be formed integrally with the bottom surface portion 23 or may be formed as a separate part made of the same or different material as the bottom surface portion 23. The width W1 of the tip end portion of the protrusion 22 is adjusted in accordance with the thickness to be formed of a collision prevention layer 25 described later. As shown in FIG. 2, two protrusions 22 are provided on the objective lens holding portion 9h1. Only one protrusion 22 may be provided, or three or more may be provided.

  Next, as shown in FIG. 6A, liquid silicone rubber 26 is applied to the entire protrusion 22 including the portion 23a of the bottom surface 23 of the base 24 by an application process (step S2). The silicon rubber 26 is an example of the “elastic member” according to the present invention, and a curable resin such as an ultraviolet curable adhesive resin or a thermosetting resin may be used as the elastic member. . At this time, the liquid silicon rubber 26 may be applied so as to cover the entire protruding portion 22 including the portion 23a of the bottom surface portion 23, and the amount of the liquid silicon rubber 26 to be applied is not controlled with high accuracy. Also good.

  Next, in the leaving step, the base 24 coated with the liquid silicon rubber 26 is left for a predetermined time (step S3). As shown in FIG. 6A, the applied liquid silicone rubber 26 covers the entire protrusion 22 including the portion 23a of the bottom surface 23 depending on the application method immediately after being applied. In this case as well, as time passes, as shown in FIG. 6B, the bottom surface 23 (that is, the portion 23a surrounded by the protrusion 22 or It flows out to the outside of the protrusion 22. Finally, as shown in FIG. 4, a first portion 25 a of the collision prevention layer 25 made of a thin film-like silicon rubber is formed at the tip end portion having the width W <b> 1 of the protruding portion 22, which is thinner than that immediately after coating. A second portion 25b of the collision prevention layer 25 is formed on the portion 23a. Alternatively, the applied liquid silicone rubber 26 may be a thin thin film at the tip of the protruding portion 22 as shown in FIG. 6B or FIG. A first portion 25a of the collision prevention layer 25 made of a silicon rubber is formed, and a second portion 25b of the collision prevention layer 25 is formed on the portion 23a. Also in this case, the structure shown in FIG. 4 is finally obtained.

  Particularly in the present embodiment, the protrusion 22 is formed in a polygonal cylindrical shape by the base forming process as described above. Therefore, even if a large amount of liquid silicon rubber 26 is applied, the protrusion 22 as a whole is formed. The liquid silicon rubber 26 can be allowed to flow out not only to the outside, but also to the portion 23 a surrounded by the protrusion 22. Therefore, it is possible to prevent adverse effects on other components and the like constituting the optical pickup by flowing out of the entire protrusion 22.

  Further, in the present embodiment, in particular, the region surrounding the bottom surface portion 23 of the protruding portion 22 facing the bottom surface portion 23 in a plan view on the bottom surface portion 23 is more than the region surrounding the bottom surface portion 23 at the tip end portion. Therefore, when the liquid silicon rubber 26 is applied, the silicon rubber 26 that has flowed out from the tip portion is likely to accumulate in a portion surrounded by the protruding portion 22.

  The surface 25as opposite to the surface facing the protrusion 22 of the first portion 25a of the anti-collision layer 25 is opposite to the surface facing the bottom surface portion 23 of the second portion 25b of the anti-collision layer 25. In order to move away from the bottom surface portion 23 rather than the surface 25bs, the height H of the protruding portion 22 from the bottom surface portion 23 is preferably made relatively high by the base forming step described above. As for the time for leaving, it is sufficient to leave it for a time such that the shape covering the protruding portion 22 of the applied liquid silicone rubber hardly or preferably does not change completely. Such a time is variable according to the surface tension, viscosity, liquid repellency, etc. on the protrusion 22 relating to the liquid silicon rubber to be applied. For this reason, it is preferable to experimentally obtain an optimal time so that the silicon rubber remains in a desired thickness at the tip of the protruding portion 22 in advance and leave it for the determined time in an actual manufacturing process.

  Next, the collision preventing layer 25 applied to the base 24 is cured by the curing process (step S4). That is, the anti-collision layer 25 made of liquid silicon rubber is cured by a curing agent added before or after application. When the collision prevention layer 25 is made of a curable resin such as an ultraviolet curable adhesive resin or a thermosetting resin, it is cured by light irradiation or heat treatment.

  Therefore, according to the manufacturing method of the collision prevention mechanism according to the present embodiment, the collision prevention mechanism 21 according to the first embodiment described above can be manufactured. In particular, a relatively thin collision prevention layer 25 can be formed easily and with high accuracy by forming a narrow width at the tip of the protruding portion 22 and applying liquid silicon rubber thereon. Accordingly, in the optical disc system, the working distance between the objective lens 8 and the optical disc D can be shortened.

(Second embodiment)
Next, a collision preventing mechanism according to a second embodiment of the present invention will be described with reference to FIGS. FIG. 7 is a perspective view showing a collision prevention mechanism according to the second embodiment of the present invention, and FIG. 8 is a sectional view taken along a line along the X direction of the collision prevention mechanism in FIG. 7 and 8, the same reference numerals are given to the same components as the components according to the first embodiment shown in FIGS. 1 to 4, and the description thereof will be omitted as appropriate. In FIG. 8, in order to make each layer / member recognizable on the drawing, the scale is different for each layer / member.

  As shown in FIGS. 7 and 8, the collision prevention mechanism 31 according to the second embodiment of the present invention includes a base 34 and a collision prevention layer 35.

  Particularly in the collision prevention mechanism according to this embodiment, the protrusion 32 of the collision prevention mechanism 31 has a plate-like shape protruding from the bottom surface 33. Also in this case, a relatively thin collision prevention layer 35 can be easily and highly accurately formed by forming the width W2 of the tip of the protrusion 32 narrow and applying liquid silicon rubber or the like thereon. it can. In particular, the thickness D3 of the anti-collision layer 35 that is finally formed on the distal end portion of the applied liquid silicon rubber or the like flows out from the distal end portion of the projecting portion 32 to the bottom surface portion 33. The width is equal to or less than the width W2. Therefore, the thickness D3 of the collision preventing layer can be reduced by forming the width W2 of the tip portion of the protruding portion 32 with relatively high accuracy. That is, it is not necessary to accurately control the coating amount of liquid silicone rubber or the like, and the thickness D3 of the collision prevention layer can be reduced. Therefore, in the optical disc system, the working distance between the objective lens 8 and the optical disc D can be shortened.

(Third embodiment)
Next, the relationship between the protruding tip width and the film thickness of the anti-collision layer in the anti-collision mechanism according to the first and second embodiments of the present invention described above will be described with reference to FIGS. FIG. 9 is an explanatory view showing a simulated protrusion that simulates the protrusion of the collision preventing mechanism according to the first and second embodiments of the present invention. FIG. 10 is a diagram showing the contents of the experiment using the simulated protrusion, FIG. 10 (a) is a table showing the width of the tip of the simulated protrusion, and FIG. 10 (b) is the collision prevention layer. It is a table | surface which shows thickness, FIG.10 (c) is a graph which shows the relationship between the width | variety of the front-end | tip part of a protrusion part, and a collision prevention layer.

  In FIG. 9, the simulated protrusions 110, 120, and 130 are formed by cutting out from the experimental substrate 100 made of aluminum. The widths W11, W12, and W13 of the tip portions of the simulated protrusions 110, 120, and 130 are 0.2 mm, 0.4 mm, and 0.6 mm, respectively. FIG. The result of having measured the width | variety of the simulated protrusion parts 110, 120, and 130 of this is shown. As shown in FIG. 10 (a), the widths W11, W12, and W13 are averaged 0.2061 mm, 0.4027 mm, and 0.6022 mm, respectively, as a result of measuring the widths at three locations for each simulated protrusion. .

  An ultraviolet curable adhesive (WORLDROCK No. 8125L manufactured by Kyoritsu Chemical Industry Co., Ltd .; viscosity 4500 ± 1000 [cP] at 25 ° C.) is applied to each of the eight positions on the simulated protrusions 110, 120 and 130, After standing for 20 seconds, curing by ultraviolet irradiation was performed. As a result, simulated anti-collision layers are formed at eight positions on the tip portions of the simulated protrusions 110, 120 and 130, respectively. Since the ultraviolet curable adhesive is applied and left for 20 seconds, the ultraviolet curable resin sufficiently flows out from the front ends of the simulated projecting portions 110, 120, and 130 to the bottom portion 101. The simulated anti-collision layer formed on the part is formed sufficiently thin.

  As shown in FIG. 10B, the thicknesses of the simulated collision prevention layers formed on the simulated protrusions 110, 120, and 130 (that is, the average values of the thicknesses of the eight collision prevention layers, respectively) are respectively It was measured as 0.016 mm, 0.058 mm and 0.100 mm.

  Therefore, as shown in the graph of FIG. 10C, there is a correlation (see the approximate straight line L1 in the figure) between the tip width of the simulated protrusion and the thickness of the simulated collision prevention layer. Therefore, the thickness of the collision preventing layer can be controlled by the width of the tip of the protrusion. In other words, the anti-collision layer can be formed without having to manage the amount of the UV curable adhesive to be applied with high accuracy.

  The present invention is not limited to the above-described embodiments, and can be appropriately changed without departing from the spirit or idea of the invention that can be read from the claims and the entire specification. The manufacturing method is also included in the technical scope of the present invention.

The collision prevention mechanism and the manufacturing method thereof according to the present invention can be used for, for example, a collision prevention mechanism provided in an optical pickup in an optical disc system.

Claims (5)

A collision prevention mechanism for preventing a collision between an objective lens mounted on an optical pickup in an optical disk system and the surface of the optical disk,
A bottom surface portion provided on the optical pickup, and a predetermined portion of the bottom surface portion that protrudes in a direction facing the optical disk on the bottom surface portion and is planarly viewed on the bottom surface portion. A base having at least one protrusion provided so as to surround the first portion with a predetermined width or to be adjacent to the one portion over the predetermined width;
On at least said protruding portions and said first portion of said base, and a collision prevention layer ing is coated soft elastic member than the material of the surface of the optical disc
With
A surface of the first anti-collision layer that faces the optical disc of the first portion of the projecting portion facing the optical disc is a second portion of the anti-collision layer that is located on the one portion of the anti-collision layer. Formed away from the bottom surface than the surface facing the optical disk.
A collision prevention mechanism characterized by that.   The collision preventing mechanism according to claim 1, wherein the elastic member includes at least an ultraviolet curable adhesive resin. The protrusion is
It is provided so as to surround the one portion with a predetermined width when viewed in plan on the bottom surface portion,
The area of the surface of the protruding portion that faces the bottom surface is larger than the area of the tip surface.
The collision prevention mechanism according to claim 1 or 2, wherein   The collision preventing mechanism according to any one of claims 1 to 3, wherein the protruding portion is formed in a cylindrical shape, an elliptical cylindrical shape, or a polygonal cylindrical shape. A collision prevention mechanism for preventing a collision between an objective lens mounted on an optical pickup in an optical disk system and a surface of an optical disk, and manufacturing a collision prevention mechanism including a base and a collision prevention layer provided on the base. A mechanism manufacturing method comprising:
The bottom surface portion provided on the optical pickup, and the width of the front end surface facing the optical disc corresponding to the thickness to be formed of the collision prevention layer are projected on the bottom surface portion in the direction facing the optical disc. At least one protrusion that is adjusted and surrounds a predetermined portion of the bottom portion with a predetermined width, or is adjacent to the one portion over the predetermined width. Forming the base having a portion;
An elastic member softer than the material of the surface of the optical disk is provided on at least the protrusion and the one part on the base, and a surface of the first part located on the tip surface is opposed to the optical disk . And a step of coating the second portion positioned on the portion so as to be farther from the bottom surface than the surface facing the optical disc .

Images