JP2006053984A - Optical unit for optical head, and optical pickup apparatus provided with the optical unit for optical head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an optical unit for optical head for easily performing mutual accurate positioning of each optical unit which is requested for a interchangeable type optical unit for optical head constituted of three optical elements. <P>SOLUTION: This optical unit has three optical elements of a first optical element, a second optical element, and a third optical element in this order from a light source side, a first mirror frame holding the first optical element, and a second mirror frame holding the second optical element and the third optical element, wherein the second mirror frame has a gap formed so that the optical element of either of the second optical element and the third optical element can be slid in the orthogonal direction to an optical axis, and the first mirror frame has an abutting part formed to be held between the first optical element and the second optical element, and has a gap formed in the diameter direction of the second mirror frame. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical head device, and more particularly to an optical unit for an optical head used in a recording device for an optical recording medium such as an optical disk or an optical pickup device of a reproducing device.

  Conventional compatibility with high-density optical discs using a blue-violet laser light source to increase recording density, DVDs using a red laser light source (Digital Versatile Disk), and CDs (Compact Disk) using an infrared laser light source An optical head device is known.

  As an optical unit used in these compatible optical heads, two phase correctors are arranged in front of the objective lens to support three types of discs: HD-DVD (High Density-DVD), DVD, and CD. Is disclosed (for example, see Patent Document 1).

In addition, a CD and DVD compatible optical head device provided with an objective lens and a phase control element, a positioning mark is formed on the objective lens and the phase control element, and the positioning mark is used in a direction perpendicular to the optical axis. An optical head device is disclosed that is fixed to one holder after positioning (optical axis alignment) (see, for example, Patent Document 2).
JP 2003-207714 A JP 2001-6203 A

  The optical unit used in the optical head described in Patent Document 1 can apply three types of light having different wavelengths to optical discs having different thicknesses as shown in FIG. However, in order to obtain an imaging characteristic as shown in the figure, accurate optical axis alignment between the objective lens and the two phase correctors is required. However, there is no description about mutual optical axis alignment between the three optical elements of Patent Document 1.

  In addition, the optical head device described in Patent Document 2 has a positioning mark used for positioning using the positioning mark in the shape of the holder, the phase control element, and the objective lens as shown in FIG. While holding the microscope for confirmation, a positioning jig is brought into contact with either the phase control element or the objective lens, and the holder, the phase control element, and the objective lens are moved in a direction perpendicular to the optical axis. The specific shape of is unknown.

  Further, when the three optical elements are positioned using the positioning marks, the holder and the three optical elements each need a shape for enabling positioning. In addition, since the objective lens of the microscope for confirming the positioning mark is also arranged close to it, a shape that can be positioned without interfering with the objective lens of the microscope is required.

  In view of the above problems, the present invention provides an optical head optical unit that can easily perform accurate positioning between optical elements required for a compatible optical head optical unit composed of three optical elements. It is intended to obtain.

  The above object is solved by the following configuration.

  1) Three optical elements of a first optical element, a second optical element, and a third optical element in order from the light source side, a first lens frame that holds the first optical element, and the second optical element And a second lens frame that holds the third optical element, and the second lens frame is one of the optical elements of the second optical element and the third optical element. A gap is formed so that the element can slide in a direction perpendicular to the optical axis, and the first lens frame has a contact portion that is sandwiched between the first optical element and the second optical element. An optical unit for an optical head, which is formed with a gap in the radial direction from the second lens frame.

2) When the radial gap formed in the first lens frame and the second lens frame is A, and the gap formed in the second lens frame is B,
A> B
1) The optical unit for optical heads.

  3) The optical unit for an optical head according to 1) or 2), wherein an outer peripheral edge portion of the second optical element is formed so as to protrude from a peripheral edge portion of the corresponding second lens frame.

  4) Three optical elements of a first optical element, a second optical element, and a third optical element in order from the light source side, a first lens frame that holds the first optical element, and the second optical element And a second lens frame that holds the third optical element, and the second lens frame is one of the optical elements of the second optical element and the third optical element. A gap is formed so that the element can slide in a direction perpendicular to the optical axis, and the first lens frame has a contact portion that is sandwiched between the first optical element and the second optical element. And a gap that is slidably fitted in the second lens frame in a radial direction so that the first optical element can slide in a direction perpendicular to the optical axis. Optical unit for the head.

5) When the gap formed in the first lens frame is A and the gap formed in the second lens frame is B,
A> B
4) The optical unit for optical heads.

  6) Either of the second optical element and the third optical element, wherein an outer peripheral edge portion of the first optical element protrudes from a corresponding peripheral edge portion of the first lens frame and is slidable. The optical head optical unit according to 4) or 5), wherein the outer peripheral edge of one of the optical elements is formed so as to protrude from the peripheral edge of the corresponding second lens frame.

  7) The first optical element, the second optical element, and the third optical element in order from the light source side, and the first optical element that holds the first optical element and the second optical element. And a second lens frame that holds the third optical element, and the first lens frame has a gap that allows the first optical element to slide in a direction perpendicular to the optical axis. And an optical head optical unit, characterized in that it is formed with a gap in the radial direction from the second lens frame.

8) A gap that allows the first optical element formed in the first lens frame to slide in a direction orthogonal to the optical axis is defined as A, and the first lens frame and the second lens frame When the gap formed in the radial direction is B,
A> B
7) The optical unit for optical heads.

  9) The optical unit for an optical head according to 7) or 8), wherein an outer peripheral edge portion of the first optical element is formed so as to protrude from a peripheral edge portion of the corresponding first lens frame.

  10) The peripheral edge portion of the first lens frame corresponding to the outer peripheral edge portion of the first optical element has protrusions protruding from the outer peripheral edge portion of the first optical element in at least three places, and the protrusion The optical head optical unit according to any one of 4) to 8), wherein an outer peripheral edge portion of the first optical element protrudes from a peripheral edge portion of the first lens frame at a position other than the portion.

  11) The optical unit for an optical head according to any one of 1) to 10), wherein the first optical element and the second optical element are optical elements having a structure in which a step is formed on a surface thereof.

  12) An optical pickup device comprising the optical unit for an optical head according to any one of 1) to 11).

  According to the present invention, it is possible to obtain an optical head optical unit that can easily perform accurate positioning between optical elements required for a compatible optical head optical unit composed of three optical elements. Can do.

  Hereinafter, the present invention will be described in detail with reference to embodiments, but the present invention is not limited thereto.

  FIG. 1 is a diagram showing an optical schematic configuration of a compatible optical pickup device 100 including an optical unit for an optical head according to the present invention.

  In the figure, a compatible optical pickup device 100 includes a blue-violet semiconductor laser 11 suitable for recording / reproduction of a high-density optical disk 19a using a blue-violet laser light source and increased in recording density, and light reflected from the high-density optical disk 19a. Detector 15 for receiving and detecting light, a first optical module 17 in which a red semiconductor laser having a wavelength of 650 nm suitable for recording / reproduction of DVD 19b and a photodetector is integrated, and a wavelength of 780 nm suitable for recording / reproduction of CD 19c. The second optical module 18 in which the infrared semiconductor laser and the photodetector are integrated, and the above three kinds of laser light are guided to the collimator lens 14 and also to the photodetector that receives the reflected light from the disk, respectively. The laser beams collimated by the beam splitters 12, 13, 16 and the collimator lens 14 are converted into the above-mentioned respective discs. Is imaged in a state that conforms to, and is configured to include an optical unit 50 for the optical head according to the present invention.

  When the high-density optical disk 19a is, for example, an HD-DVD, the blue-violet semiconductor laser 11 having a wavelength of around 400 nm is used.

  The compatible optical pickup device shown in FIG. 1 is an example, and various modifications can be made.

(First embodiment)
Hereinafter, a first embodiment of an optical unit 50 for an optical head according to the present invention will be described.

  FIG. 2 is a schematic sectional view showing an example of the optical unit 50 for an optical head according to the first embodiment.

  In the figure, an optical unit 50 for an optical head includes a first optical element 21, a second optical element 22, a third optical element 23, a first optical element 21 and a second optical element in order from the laser light source side. A contact portion 26 sandwiched between the optical elements 22 is integrally formed, and a first lens frame 25 that holds the first optical element 21, a second optical element 22, and a third optical element 23. It is comprised with the 2nd lens frame 24 which hold | maintains.

  The first lens frame 25 and the second lens frame 24 are preferably formed by molding with a light-shielding resin material.

  The first optical element 21 is an optical element mainly responsible for the function of performing compatibility between blue-violet and infrared, and is viewed from the optical axis direction using an ultraviolet curable resin on the surface of the transparent glass plate that is not on the light source side. It is preferable to form a hybrid structure in which a ring-shaped structure having a step shape with an annular shape and a stepped shape in cross section is formed as a diffraction surface. By forming the diffractive surface on the surface not exposed to the appearance in this way, it is possible to prevent the diffractive surface from being damaged. The first optical element 21 may be integrally formed of a resin material. The second optical element 22 is an optical element that is produced by injection molding of a resin material, has a diffractive surface formed on the surface on the light source side, and mainly controls the function of compatibility between blue-violet and red.

  The first optical element 21 and the second optical element 22 enable compatibility of three types of disks: a high-density optical disk, a DVD, and a CD.

  The third optical element 23 is a lens having imaging performance, and is preferably a glass molded lens (also referred to as a glass mold lens) that hardly changes with temperature. This is produced by precision molding a glass base material using a mold having a surface shape corresponding to a desired shape.

  The functional configuration of the above-described three types of optical elements is merely an example, and the present invention is not limited to this, and other modifications may be used.

  The internal structure of the optical head optical unit 50 using the optical element and the lens frame as described above and the mutual positioning of the optical elements will be described in the order of assembly.

  FIG. 3 is a diagram illustrating a state in which the third optical element 23 and the second optical element 22 are assembled to the second lens frame.

  In the figure, first, the third optical element 23 is assembled to the second lens frame 24. In this assembly, the flange portion 23f formed on the third optical element 23 is fitted and fixed as shown in the figure. Next, the second optical element 22 is placed on the second lens frame 24 as shown.

At this time, as shown, when the outer diameter of the second optical element 22 and D _2, the inner diameter of a portion the second optical element 22 of the second lens frame 24 is assembled to the W _2, W ₂ The inner diameter of the second lens frame 24 is formed such that> D ₂ and the second optical element 22 has a slidable gap (gap) in a direction orthogonal to the optical axis O. The value of the gap B = (W ₂ −D ₂ ) is preferably about 0.05 to 0.2 mm. Further, the height of the peripheral portion of the portion of the second lens frame 24 where the second optical element 22 is assembled has a difference of H ₂ so that the peripheral portion of the second optical element 22 protrudes. It is formed low. The height difference H ₂ is preferably about 0.3 to 0.8 mm.

  Next, with the second lens frame 24 fixed, three claw-shaped positioning jigs 31 arranged in three directions around the optical axis at intervals of about 120 ° are used as shown in the figure. The second optical element 22 is placed on the surface 22f formed on the second lens frame 24 with respect to the already fixed third optical element 23 in contact with the protruding corner portion of the outer peripheral edge. Positioning is performed by sliding in the direction perpendicular to the optical axis O of the third optical element 23. Thereafter, although not shown, the second optical element 22 is fixed by adhesion.

  As this positioning method, it is possible to apply the method described in Japanese Patent Application Laid-Open No. 2001-6203, in which marks formed on both optical elements are aligned while being confirmed with a microscope or the like. You may match | combine, confirming a focus position and the mark formed in the 2nd optical element 22. FIG.

  In this way, a gap is formed in the second lens frame 24 so that the second optical element 22 can slide in a direction orthogonal to the optical axis, and the outer peripheral edge of the second optical element 22 protrudes. Thus, the peripheral edge of the corresponding second lens frame 24 is formed, and the positioning jig 31 is slid by the positioning jig 31 in contact with the protruding outer peripheral edge of the second optical element 22 so that the positioning repair is performed. The tool 31 can be arranged in the direction orthogonal to the optical axis, and the second optical element 22 can be positioned without causing the positioning jig 31 to interfere with the second lens frame 24. A space where the objective lens 32 of the microscope for confirmation approaches can be secured on the optical axis O in the vicinity of the second optical element 22.

  FIG. 4 is a diagram showing a state in which the first optical element 21 assembled to the first lens frame 25 is positioned after the step shown in FIG.

  As shown in the figure, after the second optical element 22 is positioned and fixed to the third optical element 23 in the second lens frame 24, the first optical element 21 is assembled in advance. The abutment portion 26 of the lens frame 25 is placed so as to abut on the second optical element 22. The first optical element 21 is assembled with the first lens frame 25 by fitting, and is fixed by adhesion.

At this time, as shown in the drawing, when the inner diameter of the first lens frame 25 is W ₁ and the outer diameter of the second lens frame 24 is D ₁ , W ₁ > D ₁ , The inner diameter of the first lens frame 25 is formed so that the lens frame 25 has a slidable gap in the direction orthogonal to the optical axis O. The value of the gap A = (W ₁ −D ₁ ) is set to be larger than the value of B = (W ₂ −D ₂ ), that is, A> B, and is about 0.1 to 0.4 mm. preferable. By setting in this way, it is possible to prevent the sliding amount for positioning the first optical element assembled in the first lens frame from being insufficient.

  Thereafter, with the second lens frame 24 fixed, the positioning jig 31 is brought into contact with the corner of the outer peripheral edge of the first lens frame 25 as shown in the drawing, and the already fixed second optical element. The first lens frame 25 holding the first optical element 21 is slid in the direction perpendicular to the optical axis O while holding the contact portion 26 with respect to 22, and positioning is performed. Thereafter, although not shown, the first lens frame 25 is fixed to the second lens frame 24 by adhesion.

  As described above, the first lens frame 25 in which the first optical element 21 is incorporated is formed with a contact portion that contacts the second optical element 22, and is spaced from the second lens frame 24 in the radial direction. By forming the first optical element 21, the first optical element 21 can be positioned. In addition, the positioning jig 31 can be arranged in the direction perpendicular to the optical axis by sliding with the positioning jig 31 that contacts the outer peripheral edge of the first lens frame 25, and the positioning mark and the like are confirmed. Therefore, a space for the objective lens 32 of the microscope to approach can be secured on the optical axis O in the vicinity of the first optical element 21.

  Further, the distance in the optical axis direction between the first optical element 21 and the second optical element 22 can be managed only by the thickness of the contact portion 26, and the distance accuracy can be stabilized.

(Second Embodiment)
Hereinafter, a second embodiment of the optical unit 50 for an optical head according to the present invention will be described.

  FIG. 5 is a schematic cross-sectional view of another example of the optical unit 50 for an optical head according to the second embodiment. In this figure, the same members as those in the optical unit for an optical head shown in FIG. 2 are denoted by the same reference numerals to avoid duplication of explanation, and only different portions will be described.

  In the figure, the shape of the second optical element 22, the third optical element 23 and the second lens frame 24 holding them, and the positioning of the second optical element 22 and the third optical element 23 are shown in FIG. This is the same as described in 3.

  As described above, after the second optical element 22 is positioned and fixed with respect to the third optical element 23 in the second lens frame 24, the first lens frame 27 is moved to the second lens frame as shown in the figure. 24 is fitted and incorporated in the radial direction around the optical axis. At this time, in the optical axis direction, the contact portion 26 formed integrally with the first lens frame 27 is in contact with the second optical element 22, and in this state, the first lens frame 27 and the first lens frame 27 are in contact with each other. Two lens frames 24 are bonded and fixed. Thereafter, the first optical element 21 is placed on the contact portion 26 formed on the first lens frame 27.

At this time, as shown, when the outer diameter of the first optical element 21 and D _1, the inner diameter of the portion where the first optical element 21 of the first lens frame 27 is assembled to the W _1, W ₁ The inner diameter of the first lens frame 27 is formed such that> D ₁ and the first optical element 21 has a slidable gap (gap) in a direction orthogonal to the optical axis O. The value of the gap A = (W ₁ −D ₁ ) is set to be larger than the value of B = (W ₂ −D ₂ ), that is, A> B, and is about 0.1 to 0.4 mm. preferable. By setting in this way, it is possible to prevent the sliding amount for positioning the first optical element in the first lens frame from being insufficient. Further, the height of the peripheral portion of the portion of the first lens frame 27 where the first optical element 21 is assembled has a difference of H ₁ so that the peripheral portion of the first optical element 21 protrudes. It is formed low. The height difference H ₁ is preferably about 0.3 to 0.8 mm.

  Thereafter, with the second lens frame 24 fixed in the same manner as described above, the positioning jig 31 is brought into contact with the corner of the protruding outer peripheral edge of the first optical element 21 as shown in FIG. The first optical element 21 is slid in the direction perpendicular to the optical axis O on the contact portion 26 with respect to the second optical element 22 to perform positioning. Thereafter, although not shown, the first optical element 21 is fixed to the first lens frame 25 by adhesion.

  In this manner, the first lens frame 27 is formed with the contact portion 26 sandwiched between the first optical element 21 and the second optical element 22, and is fitted in the second lens frame 24 in the radial direction. The first optical element 21 forms a gap in the direction perpendicular to the optical axis on the contact portion 26, and is slid by a positioning jig that contacts the outer peripheral edge of the protruding first optical element 21. By moving, the positioning jig 31 can be arranged in the direction orthogonal to the optical axis, and the first optical element 21 can be positioned without causing the positioning jig to interfere with the first lens frame 25. Thus, a space in which the objective lens 32 of the microscope for confirming the positioning mark or the like approaches can be secured on the optical axis O in the vicinity of the first optical element 21, and each optical element can be easily positioned. become able to.

  Further, the distance in the optical axis direction between the first optical element 21 and the second optical element 22 can be managed only by the thickness of the contact portion 26, and the distance accuracy can be stabilized.

(Third embodiment)
The third embodiment of the optical head optical unit 50 according to the present invention will be described below.

  FIG. 6 is a diagram illustrating a state in which the third optical element 23 and the second optical element 22 are assembled to the second lens frame of the optical unit for an optical head according to the third embodiment.

  In the figure, first, the third optical element 23 is assembled to the second lens frame 24. In this assembly, the flange portion 23f formed on the third optical element 23 is fitted and fixed as shown in the figure. Next, the first lens frame 28 in which the second optical element 22 is assembled in advance is placed on the second lens frame 24 as shown in the figure. The second optical element 22 is assembled to the first lens frame 28 by fitting and is bonded and fixed in advance.

At this time, as shown in the figure, when the outer diameter of the second lens frame 24 is D ₂ and the inner diameter of the corresponding first lens frame 28 is W ₂ , W ₂ > D ₂ , and the first The inner diameter of the corresponding first lens frame 28 is formed so that the lens frame 28 has a slidable gap (gap) in a direction perpendicular to the optical axis O of the first optical element 21. The value of the gap B = (W ₂ −D ₂ ) is preferably about 0.05 to 0.2 mm.

  Next, with the second lens frame 24 fixed, three claw-shaped positioning jigs 31 arranged in three directions at intervals of about 120 ° are used as shown in FIG. The second optical element 22 integrated with the first lens frame 28 on the surface 22f formed on the second lens frame 24 with respect to the already fixed third optical element 23, Positioning is performed by sliding in the direction orthogonal to the optical axis O of the third optical element 23. Thereafter, although not shown, the first lens frame 28 is fixed to the second lens frame 24 by adhesion.

  FIG. 7 is a diagram showing a state in which the first optical element 21 is positioned after the step shown in FIG.

  As described above, after the second optical element 22 integrated with the first lens frame 28 is positioned and fixed with respect to the third optical element 23, the first optical element 21 is moved to the first mirror. It is placed as shown in the figure on a contact portion 26 that contacts the second optical element 22 formed in the frame 28.

At this time, the outer diameter of the first optical element 21 and D _1, when the inner diameter of the portion where the first optical element 21 of the first lens frame 28 is assembled to the W _1, W _1> D ₁ met Thus, the first lens frame 28 is formed so that the first optical element 21 has a slidable gap (gap) in a direction orthogonal to the optical axis O. The value of the gap A = (W ₁ −D ₁ ) is set to be larger than the value of B = (W ₂ −D ₂ ), that is, A> B, and is about 0.1 to 0.4 mm. preferable. By setting in this way, it is possible to prevent the sliding amount for positioning the first optical element from being insufficient. Further, the height of the peripheral portion of the portion of the first lens frame 28 where the first optical element 21 is assembled has a difference of H ₁ so that the peripheral portion of the first optical element 21 protrudes. It is formed low. The height difference H ₁ is preferably about 0.3 to 0.8 mm.

  After that, with the second lens frame 24 fixed, the positioning jig 31 is brought into contact with the corner of the protruding outer peripheral edge of the first optical element 21 as shown in the drawing, so that the already fixed second The first optical element 21 is slid in the direction orthogonal to the optical axis O on the contact portion 26 with respect to the optical element 22 to perform positioning. Thereafter, although not shown, the first optical element 21 is fixed to the first lens frame 28 by adhesion.

  Thus, the first lens frame 28 forms a gap in which the first optical element 21 can slide in a direction orthogonal to the optical axis, and has a gap in the radial direction from the second lens frame 24. The positioning jig 31 can be arranged in the direction perpendicular to the optical axis and the second optical element 22 and the first optical element 21 can be positioned, and the positioning marks and the like can be confirmed. Therefore, a space where the objective lens 32 of the microscope for approaching can be secured on the optical axis O, and positioning of each optical element can be easily performed.

  Further, the distance in the optical axis direction between the first optical element 21 and the second optical element 22 can be managed only by the thickness of the contact portion 26, and the distance accuracy can be stabilized.

  The first lens frame that holds the first optical element in the second and third embodiments is preferably shaped as follows.

  FIG. 8 is a diagram showing the shape of the tip of the first lens frame 27 or 28.

  As shown in the figure, projections T projecting from the outer peripheral edge of the first optical element 21 are provided at three positions on the peripheral edge of the first lens frame 27 or 28. The protrusions T are formed at positions that do not interfere with the positioning jigs arranged in the three directions at approximately 120 ° intervals. At a position other than the protrusion T, the outer peripheral edge of the first optical element 21 is formed so as to protrude from the peripheral edge of the first lens frame 25 or 27.

  By forming the projection T on the first lens frame 27 or 28 in this way, the completed optical head optical unit 50 can be placed with the projection T down, and after completion, Abrasion can be prevented.

  In the first and second embodiments described above, the third optical element 23 is fitted and fixed, and the second optical element 22 is positioned with respect to the third optical element 23. However, the present invention is not limited to this, and the second optical element 22 may be fitted and fixed, and the third optical element 23 may be positioned. Needless to say, it is formed in the second lens frame 24 with respect to the third optical element 23.

It is the figure which showed the optical schematic structure of the compatible optical pick-up apparatus provided with the optical unit for optical heads concerning this invention. It is a schematic sectional drawing which shows an example of the optical unit for optical heads which concerns on 1st Embodiment. It is a figure which shows the state by which a 3rd optical element and a 2nd optical element are assembled | attached to a 2nd lens frame. It is a figure which shows the state which positions the 1st optical element assembled | attached to the 1st lens frame after the process shown in FIG. It is a schematic sectional drawing of another example of the optical unit for optical heads concerning 2nd Embodiment. It is a figure which shows the state by which the 3rd optical element and 2nd optical element are assembled | attached to the 2nd lens frame of the optical unit for optical heads concerning 3rd Embodiment. It is a figure which shows the state which positions the 1st optical element after the process shown in FIG. It is a figure which shows the shape of the front-end | tip part of the 1st lens frame 27 or 28. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Blue-violet semiconductor laser 12 Beam splitter 13 Beam splitter 14 Collimator lens 15 Photo detector 16 Beam splitter 17 1st optical module 18 2nd optical module 21 1st optical element 22 2nd optical element 23 3rd optical element 24 Second lens frame 25 First lens frame (first embodiment)
27 First lens frame (second embodiment)
28 First lens frame (third embodiment)
31 Positioning jig 32 Microscope objective lens 50 Optical head optical unit 100 Compatible optical pickup device

Claims (12)

Three optical elements of a first optical element, a second optical element, and a third optical element in order from the light source side, a first lens frame that holds the first optical element, and the second optical element An element and a second lens frame holding the third optical element;
The second lens frame is formed with a gap that can slide one of the second optical element and the third optical element in a direction perpendicular to the optical axis,
The first lens frame is formed with a contact portion that is sandwiched between the first optical element and the second optical element, and is formed with a gap in the radial direction with respect to the second lens frame. An optical unit for an optical head. When the radial gap formed in the first lens frame and the second lens frame is A, and the gap formed in the second lens frame is B,
A> B
The optical unit for an optical head according to claim 1, wherein the optical unit is an optical unit. 3. The optical unit for an optical head according to claim 1, wherein an outer peripheral edge portion of the second optical element is formed so as to protrude from a peripheral edge portion of the corresponding second lens frame. Three optical elements of a first optical element, a second optical element, and a third optical element in order from the light source side, a first lens frame that holds the first optical element, and the second optical element An element and a second lens frame holding the third optical element;
The second lens frame is formed with a gap that can slide one of the second optical element and the third optical element in a direction perpendicular to the optical axis,
The first lens frame is formed with a contact portion sandwiched between the first optical element and the second optical element, and is fitted and fixed in the radial direction with the second lens frame. An optical unit for an optical head, wherein a gap is formed in which the first optical element is slidable in a direction perpendicular to the optical axis. When the gap formed in the first lens frame is A and the gap formed in the second lens frame is B,
A> B
The optical unit for an optical head according to claim 4, wherein the optical unit is an optical unit. An outer peripheral edge portion of the first optical element protrudes from a corresponding peripheral edge portion of the first lens frame and is slidable, and is either one of the second optical element and the third optical element. 6. The optical unit for an optical head according to claim 4, wherein an outer peripheral edge portion of the optical element is formed so as to protrude from a peripheral edge portion of the corresponding second lens frame. Three optical elements, a first optical element, a second optical element, and a third optical element, in order from the light source side, and a first lens frame that holds the first optical element and the second optical element And a second lens frame for holding the third optical element,
The first lens frame is formed with a gap that allows the first optical element to slide in a direction perpendicular to the optical axis, and has a gap in the radial direction with respect to the second lens frame. An optical unit for an optical head. A gap that allows the first optical element formed in the first lens frame to slide in a direction orthogonal to the optical axis is A, and the radial direction between the first lens frame and the second lens frame. When the gap formed in B is B,
A> B
The optical unit for an optical head according to claim 7, wherein the optical unit is an optical unit. 9. The optical unit for an optical head according to claim 7, wherein an outer peripheral edge portion of the first optical element is formed so as to protrude from a peripheral edge portion of the corresponding first lens frame. The peripheral edge portion of the first lens frame corresponding to the outer peripheral edge portion of the first optical element has protrusions protruding from the outer peripheral edge portion of the first optical element in at least three places, and other than the protrusion portions. 9. The optical head optical unit according to claim 4, wherein an outer peripheral edge portion of the first optical element protrudes from a peripheral edge portion of the first lens frame at the position of 5. . 11. The optical head according to claim 1, wherein the first optical element and the second optical element are optical elements having a structure in which a step is formed on a surface thereof. Optical unit. An optical pickup device comprising the optical unit for an optical head according to claim 1.

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