JP2007157293A - Structure of mounting launch mirror on base member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a structure of mounting a launch mirror on a base member, which suppresses degradation in aberration of the launch mirror even if the temperature is changed. <P>SOLUTION: A launch mirror 1 is in a rectangular plate shape, and the edges at horizontally two sides of the mirror 1, which sandwich an optical path between them, are set on seating surfaces 21, 22, and an end face 13 at a front side between longitudinally two sides is contacted to a protrusion 23 formed on the base member 2. A left end face 11 as one of horizontally two sides is adhesively fixed to the seating surface 21 by curing of UV curable adhesives 3A, 3B coated at two points with a space, and a right end face 12 as the other of horizontally two sides is adhesively fixed to the seating surface 22 by curing of thermosetting adhesives 4A, 4B coated at two points with a space. The UV curable adhesives 3A, 3B have lower in hardness after curing than the thermosetting adhesives 4A, 4B. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a structure for mounting a launch mirror on a base member in an optical pickup for reproducing and recording information on an optical disc such as a CD or DVD as an information recording medium.

  In general, an optical pickup device includes an optical pickup that reciprocates in a radial direction along the recording surface of a rotating optical disk. This optical pickup is mainly a light source such as a laser diode that emits light such as laser light, a photodiode that finally receives and detects return light from an optical disk based on the light from the light source, and converts it into an electrical signal, etc. Optical detectors, mirrors that guide the light from the light source to the optical detectors through reflection of the optical disk, optical systems such as diffraction gratings and objective lenses, and base members that are driven by attaching these components .

  An example of the arrangement of the optical system in such an optical pickup is shown in FIGS. Here, FIG. 4 shows an A arrow view of FIG. In this optical pickup, the light source 51 is disposed so as to emit light parallel to the recording surface 57 a of the optical disk 57. The light emitted from the light source 51 is split through the diffraction grating 52, and then is reflected once by the half mirror 53 in parallel with the recording surface 57 a of the optical disk 57 and guided to the launch mirror 1. The light is reflected by the launch mirror 1 toward the recording surface 57 a of the optical disk 57. In the optical path between the launch mirror 1 and the recording surface 57a of the optical disc 57, a collimating lens 54 and an objective lens 55 are disposed. Thereafter, the light is condensed on the recording surface 57 a of the optical disk 57 by the subsequent objective lens 55.

  The light is reflected by the recording surface 57a of the optical disk 57, returns to the launch mirror 1 through the objective lens 55 and the collimating lens 54 in order. The return light that has returned to the launch mirror 1 is reflected by the launch mirror 1 in parallel with the recording surface 57 a of the optical disk 57 and returns to the half mirror 53. The return light passes through the half mirror 53 and is guided to the photodetector 56. The photodetector 56 receives and detects the return light from the recording surface 57a of the optical disc 57 and converts it into an electrical signal. Thus, the recording information on the recording surface 57a of the optical disc 57 is acquired as a reproduction signal. In addition, tracking and focusing correction signals for the objective lens 55 are also generated.

  Here, when mounting the launch mirror 1 to the base member, the launch mirror 1 is generally fixed to the base member by bonding with an adhesive. An example of a conventional technique for the mounting structure (see, for example, Patent Document 1) will be described with reference to FIGS.

  The launch mirror 1 used here is a rectangular plate and is a total reflection mirror made of a glass plate or the like. The base member 2 is a molded product made of a hard resin engineering plastic such as polyphenylene sulfide (PPS). As shown in FIGS. 5 and 6, on the back surface of the base member 2, a pair of seating surfaces 21 and 22 for mounting the launch mirror 1 in a posture inclined by 45 degrees includes an optical path (bold line). Are formed at a predetermined interval so as to exist. On the respective seat surfaces 21 and 22, the left and right edges sandwiching the optical path of the launch mirror 1 are respectively placed. Further, a protrusion 23 is formed on the back surface of the base member 2 so as to bridge the ends of the seating surfaces 21 and 22. The launch mirror 1 on which the left and right edges are placed on the respective seat surfaces 21 and 22 is positioned with the front end face 13 which is one of the front and rear sides being in contact with the protrusion 23.

  In such a state, UV curable bonding is applied to the corner formed by the rear end face 14 which is the other of the front and rear sides of the launch mirror 1 and the seating surfaces 21 and 22, one on each side. The agents 103A and 103B are applied, and then irradiated with ultraviolet rays for a predetermined time to cure the ultraviolet curable adhesives 103A and 103B. As a result, the rear end face 14 of the launch mirror 1 and the seating surfaces 21 and 22 are bonded, and the launch mirror 1 is primarily bonded and fixed to the base member 2.

Subsequently, the thermosetting adhesives 104A and 104B are provided at two corners at left and right symmetrically at the corners formed by the left and right end surfaces 11 and 12 and the respective seating surfaces 21 and 22 in the launch mirror 1. , 104C and 104D, and then heated for a predetermined time to cure the thermosetting adhesives 104A, 104B, 104C and 104D. As a result, the left and right end surfaces 11, 12 and the seating surfaces 21, 22 of the launch mirror 1 are bonded, and the launch mirror 1 is completely bonded and fixed to the base member 2. This completes the mounting of the launch mirror 1 to the base member 2.
JP 2004-109843 A

  However, in the mounting structure of the launch mirror 1 to the base member 2 described above, the aberration of the launch mirror 1 may be remarkably deteriorated as the temperature changes. The cause is considered to be distortion of the launch mirror 1 with temperature change, and one reason is related to the application position of the thermosetting adhesives 104A, 104B, 104C, 104D. That is, the thermosetting adhesives 104A, 104B, 104C, and 104D themselves have a hard hardness after curing, and hardly undergo elastic deformation. However, in the mounting structure described above, the launch mirror 1 is Since the left and right end faces 11 and 12 are bonded and fixed by thermosetting adhesives 104A, 104B, 104C, and 104D applied to a total of four points, the left and right directions are firmly restrained. The thermal expansion and contraction in the left-right direction of the mirror 1 is not sufficiently released, and as a result, the launch mirror 1 is distorted.

  Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide a structure for mounting a launch mirror to a base member that can suppress deterioration of aberration of the launch mirror even when there is a temperature change. It is.

  In order to achieve the above object, the present invention provides a launch mirror that is attached to a base member that moves in a radial direction along a recording surface of an optical disc and reflects light emitted and guided from a light source toward the recording surface of the optical disc. The launch mirror has a rectangular plate shape and is a total reflection mirror that reflects return light from the recording surface of the optical disk in parallel with the recording surface of the optical disk, and sandwiches the optical path between them. The left and right edges are placed on the seat surface formed on the base member, and one of the front and rear sides is in contact with the ridge formed on the base member, and the other of the front and rear sides The end surface and the seating surface are bonded and fixed by the curing of the first adhesive applied one point to the left and right, and the left and right end surfaces and the seating surface are applied symmetrically and spaced two points apart. 2. Adhesive curing Therefore, the second adhesive is a thermosetting adhesive, and the first adhesive is an ultraviolet curable adhesive that is softer after curing than the second adhesive. The structure for mounting the launch mirror to the base member is characterized by the following points. Instead of the application position of the first adhesive and the application position of the second adhesive, the launch mirror was applied at two points with one end surface and the seating surface of the left and right sides spaced apart from each other. Bonded and fixed by curing of the first adhesive, and the other end surface of the left and right sides and the seating surface are bonded and fixed by curing of the second adhesive applied to the two points at an interval. The two points where the first adhesive is applied and the two points where the second adhesive is applied are symmetrical with each other.

  In this way, the launch mirror is bonded and fixed at one of the left and right sides with the first adhesive that is softer after curing than the second adhesive and is rich in elastic deformation. The other end surfaces of the left and right sides are bonded and fixed with a second adhesive having a hard hardness after curing. If it does so, the thermal expansion and contraction of the launching mirror accompanying the temperature change is permitted by the elastic deformation of the first adhesive, and as a result, the launching mirror is hardly distorted.

  In order to achieve the above object, the present invention is attached to a base member that moves in a radial direction along the recording surface of the optical disc, and reflects the light emitted and guided from the light source toward the recording surface of the optical disc. The launch mirror has a rectangular plate shape, and is mounted on a seat surface formed on the base member with both right and left edges sandwiching the optical path. At the same time, one end surface of the front and rear sides is in contact with the protrusion formed on the base member, and one end surface of the left and right sides and the seating surface are applied at two points with a gap therebetween. The adhesive is fixed by the curing of the adhesive, and the other end surface of the left and right sides and the seating surface are bonded and fixed by the curing of the second adhesive applied at two points with an interval between them. The agent is harder after curing than the second adhesive. It has become soft.

  In this way, the launch mirror is bonded and fixed at one of the left and right sides with the first adhesive that is softer after curing than the second adhesive and is rich in elastic deformation. The other end surfaces of the left and right sides are bonded and fixed with a second adhesive having a hard hardness after curing. If it does so, the thermal expansion and contraction of the launching mirror accompanying the temperature change is permitted by the elastic deformation of the first adhesive, and as a result, the launching mirror is hardly distorted.

  Here, it is preferable that the two points where the first adhesive is applied and the two points where the second adhesive is applied are symmetrical to each other.

  In view of practicality, it is preferable that the first adhesive is an ultraviolet curable adhesive and the second adhesive is a thermosetting adhesive.

  Practically, the launch mirror is preferably a total reflection mirror that reflects the return light from the recording surface of the optical disk in parallel with the recording surface of the optical disk.

  According to the mounting structure of the launch mirror to the base member of the present invention, the thermal expansion and contraction of the launch mirror in the left-right direction accompanying the temperature change is allowed by the elastic deformation of the first adhesive. As a result, the launch mirror is hardly distorted. Therefore, even if there is a temperature change, it is possible to suppress the deterioration of the aberration of the launch mirror.

  Hereinafter, a structure for mounting a launch mirror to a base member according to an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a plan view showing a structure for mounting a launch mirror to a base member according to an embodiment of the present invention, and shows a state in which the base member is viewed from the back side. FIG. 2 is a cross-sectional view showing the main part. In the figure, the same reference numerals are given to the portions having the same names and the same functions as those in FIGS.

  The launch mirror 1 in the present embodiment is a total reflection mirror made of a glass plate or the like, which is a rectangular plate like the conventional one. The base member 2 is also a molded product made of a hard plastic engineering plastic such as PPS, as in the prior art, and a pair of left and right edges of the launch mirror 1 are placed on the back surface thereof. The seating surfaces 21 and 22 and the positioning ridge 23 on which the front end surface 13 of the mounted launching mirror 1 abuts are formed.

  However, in the present embodiment, the application state of the adhesive is greatly different from the conventional one. In other words, the left side which is one of the left and right sides of the launch mirror 1 in which the left and right edges are placed on the respective seating surfaces 21 and 22 and the front end face 13 is positioned in contact with the ridge 23. Two corners of UV curable adhesives 3A and 3B are applied to the corner formed by the end surface 11 and the seating surface 21 at an interval in the front and rear directions, and then irradiated with ultraviolet rays for a predetermined time to cure ultraviolet rays. Adhesives 3A and 3B are cured. As a result, the left end surface 11 and the seating surface 21 of the launch mirror 1 are bonded, and the launch mirror 1 is primarily bonded and fixed to the base member 2.

  Subsequently, at the corner formed by the right end face 12 which is the other of the right and left sides of the launch mirror 1 and the seating face 22, two points are provided at intervals in the front and rear, and the ultraviolet curable adhesives 3A and 3B. The thermosetting adhesives 4A and 4B are applied so as to be exactly symmetrical with respect to the application position, and then heated for a predetermined time to cure the thermosetting adhesives 4A and 4B. As a result, the right end surface 12 and the seating surface 22 of the launch mirror 1 are bonded, and the launch mirror 1 is completely bonded and fixed to the base member 2. This completes the mounting of the launch mirror 1 to the base member 2.

  With such a mounting structure, the launch mirror 1 has a left-side end surface 11 that is one of the left and right sides, which is softer than the thermosetting adhesives 4A and 4B, and is harder to be elastically deformed. Bonded and fixed with rich UV curable adhesives 3A and 3B, while fixing the right end surface 12 which is the other of the left and right sides with hardened thermosetting adhesives 4A and 4B Will be. If it does so, the thermal expansion and contraction of the launch mirror 1 accompanying the temperature change is permitted by the elastic deformation of the ultraviolet curable adhesives 3A and 3B, and as a result, the launch mirror 1 is hardly distorted. Accordingly, it is possible to suppress the deterioration of the aberration of the launch mirror 1 even if the temperature changes.

  In addition, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, in the above-described embodiment, the UV curable adhesives 3A and 3B are applied and fixed to the left end surface 11 of the left and right sides of the launch mirror 1, and the thermosetting adhesive is applied to the right end surface 12. 4A and 4B were applied and bonded and fixed, but as long as adhesives with different hardness after curing were applied on both left and right sides, they could be reversed on the left and right, and the material type of the adhesive was limited Absent. Further, the application positions of the UV curable adhesives 3A and 3B applied to the two points and the application positions of the thermosetting adhesives 4A and 4B applied to the two points are individually spaced. As long as it is left-right asymmetrical.

  Further, in the above embodiment, the positioning protrusion 23 is formed so as to contact the front end face 13 of the front and rear sides of the launch mirror 1, but instead of this, the launch mirror 1 may be formed so as to be in contact with the rear end surface 14. The launch mirror 1 is not limited to the total reflection mirror that reflects the return light from the recording surface 57a of the optical disk 57 in parallel with the recording surface 57a of the optical disk 57, but can also be applied to a half mirror that transmits the return light. It is.

  INDUSTRIAL APPLICABILITY The present invention is useful for an optical pickup that is mounted on an optical pickup device for reproducing and recording information on an optical disc.

It is a top view which shows the attachment structure of the launch mirror to the base member which is one Embodiment of this invention. It is sectional drawing which shows the principal part of FIG. It is a figure which shows an example of the arrangement configuration of the optical system in the conventional general optical pick-up apparatus. It is A arrow directional view of FIG. It is a top view which shows the attachment structure of the launch mirror to the conventional base member. It is sectional drawing which shows the principal part of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Launching mirror 11 End face on the left side of launching mirror 12 End face on the right side of launching mirror 13 End face on the front side of launching mirror 14 End face on the rear side of launching mirror 2 Base member 21, 22 Seating surface 23 Projection 3A, 3B UV curable Adhesive 4A, 4B Thermosetting adhesive

Claims (5)

An attachment structure to a base member of a launch mirror that is attached to a base member that moves in a radial direction along the recording surface of the optical disc and reflects light emitted and guided from the light source toward the recording surface of the optical disc,
The launch mirror has a rectangular plate shape and is a total reflection mirror that reflects the return light from the recording surface of the optical disk in parallel with the recording surface of the optical disk. The right and left edges sandwiching the optical path are formed on the base member. And one end face of both front and rear sides abuts on the ridge formed on the base member, and the other end face and the seat face of the front and rear sides are one point on the left and right. Bonded and fixed by curing the first adhesive applied one by one, and the end surfaces on both the left and right sides and the seating surface are symmetrically spaced and bonded and fixed by curing the second adhesive applied two points at a time. And
The second adhesive is a thermosetting adhesive, and the first adhesive is an ultraviolet curable adhesive having a softer hardness after curing than the second adhesive. In the mounting structure,
Instead of the application position of the first adhesive and the application position of the second adhesive, the launch mirror was applied at two points with one end surface and the seating surface of the left and right sides spaced apart from each other. Bonded and fixed by curing of the first adhesive, and the other end surface of the left and right sides and the seating surface are bonded and fixed by curing of the second adhesive applied to the two points at an interval,
2. A structure for mounting a launch mirror to a base member, wherein the two points where the first adhesive is applied and the two points where the second adhesive is applied are symmetrical to each other. An attachment structure to a base member of a launch mirror that is attached to a base member that moves in a radial direction along the recording surface of the optical disc and reflects light emitted and guided from the light source toward the recording surface of the optical disc,
The launch mirror has a rectangular plate shape, and both left and right edges sandwiching the optical path are placed on the seat surface formed on the base member, and one end surface of the front and rear sides is the base member. Abutting on the formed ridge, one end surface of the left and right sides and the seating surface are bonded and fixed by the curing of the first adhesive applied to the two points at an interval. The other end surface and the seating surface are bonded and fixed by curing of the second adhesive applied to the two points at an interval,
A structure for mounting a launch mirror to a base member, wherein the first adhesive is softer after curing than the second adhesive.   The launch to the base member according to claim 2, wherein the two points where the first adhesive is applied and the two points where the second adhesive is applied are symmetrical to each other. Mirror mounting structure.   The launch mirror to the base member according to claim 2 or 3, wherein the first adhesive is an ultraviolet curable adhesive and the second adhesive is a thermosetting adhesive. Mounting structure.   The launch mirror to the base member according to any one of claims 2 to 4, wherein the launch mirror is a total reflection mirror that reflects return light from the recording surface of the optical disk in parallel with the recording surface of the optical disk. Mounting structure.

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