WO2012164938A1

WO2012164938A1 - Optical pickup device and objective lens

Info

Publication number: WO2012164938A1
Application number: PCT/JP2012/003573
Authority: WO
Inventors: 謙一今井
Original assignee: 三洋電機株式会社
Priority date: 2011-05-31
Filing date: 2012-05-31
Publication date: 2012-12-06
Also published as: JP2014157637A

Abstract

Provided are an optical pickup device, for which an objective lens is well fixed to a lens holder, and an objective lens used therefor. The objective lens (40) provided in this optical pickup device has a lens section (42) and a flange section (44) that is continuously integrated with the perimeter of the lens section (42). The side surface of the flange section (44) is formed into a tilted surface (46) inclining inwards at the top. As a result, the contact area between a fixation material (60) used for fixing the objective lens (40) and the tilted surface (46) is increased, so that the objective lens (40) is firmly fixed to the lens holder (32).

Description

Optical pickup device and objective lens

The present invention relates to an optical pickup device used for reading and writing of an optical disc and an objective lens provided therein.

In an optical pickup apparatus that optically reads or writes signals to an optical disc, an objective lens holder attached with an objective lens is supported so as to be displaceable with respect to an actuator frame. In addition, the focusing coils and the like are attached to the lens holder, and the effective regions of these drive coils are arranged in a predetermined magnetic field formed by the magnetic circuit, thereby driving the objective lens according to the signals supplied to each drive coil. (See Patent Document 1 below).

A configuration in which the objective lens 102 is attached to the lens holder 100 in a general optical pickup device will be described with reference to FIG. The objective lens 102 is composed of a lens portion 104 through which laser light passes, and a flange portion 106 provided so as to surround the periphery of the lens portion 104. The lower surface of the flange portion 106 of the objective lens 102 contacts the upper surface of the lens holder 100, whereby the objective lens 102 is mounted on the lens holder 100. The objective lens 102 is fixed to the lens holder 100 by applying the fixing material 108 so as to contact the side surface of the flange portion 106 and the upper surface of the lens holder 100.

JP 2008-222622 A

However, in the fixing structure of the objective lens 102 described above, there is a problem that the objective lens 102 can not be fixed well.

Specifically, when the objective lens 102 is placed on the upper surface of the lens holder 100, the side surface of the flange portion 106 of the objective lens 102 is perpendicular to the upper surface of the lens holder 100. Therefore, when the dispenser for supplying the adhesive 108 is brought close to the objective lens 102 in order to cause the adhesive 108 to adhere well to the side surface of the flange 106 in the application process of the adhesive 108, the dispenser will move to the flange 106. The objective lens 102 may move to cause a defect.

Further, since the side surface of the flange portion 106 is a vertical surface, the area in which the fixing material 108 contacts the side surface of the flange portion 106 is small, and the effect of fixing the objective lens 102 to the lens holder 100 by the fixing material 108 is small. There was also fear.

The present invention has been made in view of the above problems. An object of the present invention is to provide an optical pickup device in which an objective lens is well fixed to a lens holder, and an objective lens used therefor.

The optical pickup device according to the present invention comprises an objective lens for condensing laser light on the information recording layer of the optical disc, and a lens holder to which the objective lens is fixed, and the objective lens transmits the laser light. A lens portion, a flange portion surrounding the lens portion, a first main surface of the flange portion facing the lens holder, a second main surface facing the first main surface, the first main surface and the first main surface And a side surface connecting the second main surface, wherein the outer peripheral end of the second main surface of the flange portion is positioned inward of the outer peripheral end of the first main surface, and the side surface of the objective lens The objective lens is fixed to the lens holder by a fixing material contacting the surface of the lens holder.

The objective lens according to the present invention includes a lens portion through which laser light is transmitted, a flange portion integrally molded so as to surround the lens portion, a first main surface of the flange portion, and a first surface facing the first main surface. The outer peripheral end of the second main surface of the flange portion has a main surface and a side surface connecting the first main surface and the second main surface. It is also characterized in that it is placed inside.

According to the present invention, the outer peripheral end of the second main surface of the flange portion is disposed inside the outer peripheral end of the first main surface of the flange portion facing the lens holder. As a result, the area of the outer side surface of the flange portion is increased, the area in which the fixing material adheres to the outer side surface of the flange portion is increased, and the objective lens is firmly fixed to the lens holder by the fixing material.

In addition, since the outer peripheral end of the second main surface of the flange portion is disposed inside, there is a risk that the tip portion of the dispenser contacts the flange portion of the objective lens even if the adhesive is supplied by the dispenser in the manufacturing process. You can reduce the sex.

It is a figure which shows the optical pick-up apparatus of this invention. It is a figure which shows the objective lens of this invention, (A) is a perspective view, (B) is sectional drawing, (C) and (C1) are sectional drawings which show the other shape of an objective lens, D) is a plan view showing another embodiment. It is a figure which shows the objective lens of this invention, (A) is a perspective view, (B) and (B1) are sectional views, (C) is a sectional view showing other shapes of an objective lens. It is a figure which shows the structure by which an objective lens adheres to a lens holder in the optical pick-up apparatus of this invention, (A) is a perspective view, (B) and (C) are sectional views, (D) and (E) is a cross-sectional view showing another form of the fixing structure. It is a perspective view which shows the lens holder used for the optical pick-up apparatus of this invention. It is a figure which shows the manufacturing method of the objective lens of this invention, (A) is a top view which shows the metal mold | die used, (B) is sectional drawing of a metal mold, (C) is the objective manufactured. It is sectional drawing which shows a lens partially, (D) is a top view which shows the metal mold | die of another form. It is sectional drawing which shows the optical pick-up apparatus of background art partially.

The basic configuration of the optical pickup device of the present embodiment will be described with reference to FIG.

The optical pickup device 10 focuses laser light of BD (Blu-ray Disc), DVD (Digital Versatile Disk) or CD (Compact Disk) standard on the information recording layer of the optical disc (information recording medium), and this information recording is performed. It has a function of receiving the reflected light from the layer and converting it into an electrical signal. Here, the optical pickup device 10 does not necessarily have to correspond to laser beams of three types of standards, and may correspond to laser beams of one or two standards.

The specific configuration of the optical pickup device 10 includes a housing 12 and various optical elements incorporated in the housing 12. As an optical element, a laser unit 14, a diffraction grating 16, a half mirror 22, a quarter wavelength plate 24, a collimator lens 26, an objective lens 40, and a light detector 18 are illustrated. Further, at the upper and lower ends in the drawing of the housing 12, an engaging portion 34 with which the guide shaft is engaged and an insertion portion 36 through which the guide shaft is inserted are provided.

The objective lens 40 is fixed to the upper surface of the lens holder 32, and the lens holder 32 is held by the objective lens driving device 28 in a movable state via a wire.

The laser unit 14 includes a laser diode, and the laser beam of the above-described standard is emitted from the laser diode. Specifically, laser light of blue-violet (blue) wavelength band 395 nm to 420 nm (for example, wavelength of 405 nm) suitable for BD, laser light of red wavelength band 645 nm to 675 nm (for example, wavelength of 650 nm) Laser light in the infrared wavelength band 765 nm to 805 nm (for example, a wavelength of 780 nm) suitable for CD is emitted from the laser diode.

The laser light emitted from the laser unit 14 is separated into 0th-order light, + 1st-order light and -1st-order light by the diffraction grating 16 and reflected by the half mirror 22, and then the quarter wavelength plate 24 and the collimator lens 26. And is reflected by a raising mirror (not shown) and focused on the information recording layer of the optical disc by the objective lens 40. Then, the laser beam of the return light reflected by the information recording layer of the optical disk passes through the rising mirror, the collimator lens 26, the quarter wavelength plate 24, and the half mirror 22 and then is detected by the light detector 18 (PDIC) Be done. A control signal is supplied to the coil of the lens holder 32 based on the signal detected by the light detector 18. As a result, focus control, tracking control and radial tilt control are performed.

The objective lens 40 of this embodiment will be described with reference to FIG. 2A is a perspective view showing the objective lens 40, FIG. 2B is a cross-sectional view taken along the line BB 'in FIG. 2A, and FIG. 2C is a cross-sectional view of the objective lens 40. It is sectional drawing which shows another form.

Here, the vertical range and the tilt range will be described with respect to the side surface of the flange portion. The conventional structure shown in FIG. 7 is a case where the side surface is formed vertically, and the ease of taking it from the mold is taken into consideration, and a slight drafting taper angle may be provided. For example, in Japanese Patent Application Laid-Open No. 2008-119830 and the like, in FIG. 7 of the present application, the side surface is inclined inward from the upper surface to the back surface of the flange portion, and the angle is about 0 degrees to 5 degrees. That is, the ease of removal is taken into consideration, and it is considered that the degree of inclination in this range is inward inclination from the upper surface of the flange portion and outward inclination is a vertical side surface.

Referring to FIG. 2A, the objective lens 40 includes a lens portion 42 at a central portion and a flange portion 44 surrounding the lens portion 42. The lens unit 42 has a function of focusing the laser beam emitted from the laser diode on the information recording layer of the optical disk. The flange portion 44 is a portion that contacts the lens holder when the objective lens 40 is fixed to the lens holder. When the objective lens 40 is viewed from above, it has a substantially circular shape, and the side surface of the flange portion 44 is visible. This is realized by making the side surface of the flange portion 44 an inclined surface or a stepped shape as described later. As a material of the objective lens 40, an olefin resin material is employed.

Referring to FIGS. 2A and 2B, the upper and lower surfaces of lens portion 42 have a curved shape for focusing laser light incident from above. Then, a flange portion 44 is provided around the lens portion 42, and when the objective lens 40 is fixed to the lens holder, the lower surface of the entire periphery of the flange portion 44 contacts the lens holder. The flange portion 44 is an inclined surface 46 connecting the first major surface 45 which is the lower surface on the paper surface, the second major surface 47 facing the first major surface 45, and the first major surface 45 and the second major surface 47. (Side surface) and extends in a ring shape in plan view.

The first main surface 45 is a surface that contacts the lens holder of the optical pickup device, and is a flat surface perpendicular to the traveling direction of the laser beam passing through the objective lens 40, and the top part under the lens portion 42 It is located on the front side (upper surface side) than it is. The second major surface 47 is a plane substantially parallel to the first major surface 45, and is disposed above the upper end of the lens portion 42. Thereby, for example, the upper surface of the lens portion 42 can be protected by the second main surface 47 which is the upper end portion of the flange portion 44 under use conditions or in the middle of the manufacturing process.

As will be described later with reference to FIG. 6, the objective lens 40 is made by molding plastic with a mold. Although the resin is not particularly limited, it is transparent to light and is, for example, the above-mentioned olefin resin. In the objective lens 40, the lens portion 42 and the flange portion 44 are integrally molded by a mold. The lens unit 42 has a first curved surface and a second curved surface on which light can be focused, and is circular when viewed from above. Further, the flange portion 44 is in the form of a ring having a substantial thickness, and the inner diameter is slightly larger than the lens portion 42, and the outer side surface is inclined. The cylindrical hollow part in the inside of the flange has a shape in which the slip and the lens part 42 are contained, and there is a boundary part connecting the lens part 42 and the flange part 44.

In the present embodiment, the outer peripheral end of the second main surface 47 of the flange portion 44 is disposed inside the outer peripheral end of the first main surface 45. And the inclined surface 46 which connects the 1st main surface 45 of the flange part 44 and the 2nd main surface 47 is the inclined surface 46 to which an upper part turns inside. Here, the angle θ at which the inclined surface 46 tilts from the vertical surface is, for example, 15 degrees or more and 60 degrees or less. Thereby, the structure to which the objective lens 40 is fixed is strengthened, and there is an effect that the application of the fixing material becomes easy. The details of this effect will be described with reference to FIG.

Here, the entire side surface of the flange portion 44 may be the inclined surface 46, and only the side surface to which the fixing material is attached when fixed to the lens holder is the inclined surface 46, and the other side surface is the first main surface 45 It may be a plane perpendicular to (or a slope inclined slightly inward). As described above, this perpendicular surface is considered as a vertical surface even if the angle θ is about 0 to 5 degrees, considering the extraction angle. Furthermore, although the inclined surface 46 has a linearly inclined cross-sectional shape here, the cross-sectional shape of the inclined surface 46 may be a curved shape that bulges outward or inward.

Referring to FIG. 2C, here, the outer peripheral end of the second main surface 47 is made from the outer peripheral end of the first main surface 45 by forming the side surface of the flange portion 44 as the stepped portion 48 in a step-like shape. Also placed inside. As described above, by forming the side surface of the flange portion into a step shape, the objective lens 40 can be easily moved by holding the step portion 48 in the manufacturing process of the optical pickup device.

Here, the step portion 48 has a step-like shape having a vertical surface and a horizontal surface, but the side surface of the flange portion 44 may be configured by a step portion formed of an inclined surface (non-vertical surface and non-horizontal surface) (see FIG. 2 (C1)). Furthermore, although the stepped portion 48 has a stepped shape in one step, a stepped shape in two or more steps may be employed.

Referring to FIG. 2D, most of the outer peripheral side of flange portion 44 is a vertical surface or a slightly inclined inclined surface, and two or more are disposed evenly balanced. Here, a two-piece arrangement is illustrated, and the side surfaces of the left and right end portions opposed to each other on the paper surface are the above-described inclined surface 46 or the step surface.

Another form of the objective lens 40 will be described with reference to FIG. The basic shape of the objective lens 40 described with reference to this figure is the same as that described with reference to FIG. 2 and differs in that it has a concave area 50 (cut out portion) and a projection 52. 3 (A) is a perspective view showing the objective lens 40, FIG. 3 (B) is a cross-sectional view taken along the line BB 'of FIG. 3 (A), and FIG. It is sectional drawing which shows another shape.

Referring to FIGS. 3A and 3B, concave region 50 is provided by partially cutting off flange portion 44 of objective lens 40. Here, the side surface of the flange portion 44 is the inclined surface 46 as a whole, and the side surface of the flange portion 44 located in the concave region 50 is also the inclined surface 46A.

Further, referring to FIG. 3 (B), a projecting portion 52 which protrudes laterally from the inclined surface 46A located in the concave region 50 is provided. By providing the protruding portion 52, the fixing material (adhesive agent) used for fixing the objective lens 40 is embedded in the protruding portion 52, and the effect that the fixing material adheres well to the objective lens 40 can be obtained. Here, the protrusion 52 protrudes leftward from the inclined surface 46A in the drawing, but the tip of the protrusion 52 is disposed inside the outer peripheral portion of the first main surface 45 of the flange 44 There is. As a result, the protrusion 52 is prevented from protruding outward from the outer peripheral edge of the inclined surface of the objective lens 40, and the protrusion 52 is caught and damaged by an external member in use conditions and during manufacture. Is suppressed. Here, the protrusion 52 is disposed inside the recessed region 50, but the protrusion 52 is simply disposed on the inclined surface 46 without providing the recessed region 50 as shown in FIG. 3 (B1), and the protrusion The end of the portion 52 may be disposed inside the end of the first major surface 45 of the flange 44.

With reference to FIG. 3C, in the structure in which a step 48 comprising a horizontal surface and a vertical side surface is provided on the entire side surface of the flange portion 44, the above-described recessed region 50 is provided. The protrusion 52 may be provided. Even with such a structure, the effects described above can be obtained.

The lens holder 32 provided with the objective lens 40 having the above-described configuration will be described with reference to FIG. 4 (A) is a perspective view showing the lens holder 32 to which the objective lens 40 is fixed, and FIG. 4 (B) is a cross-sectional view taken along line BB 'of FIG. 4 (A). C) is a cross-sectional view showing another configuration to which the objective lens 40 is fixed.

Referring to FIG. 4A, objective lens 40 is fixed in the vicinity of the central portion of the upper surface of lens holder 32, and protective portion 58 is provided on the upper surface of lens holder 32 at a position surrounding the periphery of objective lens 40. ing. Further, in the left and right direction of the lens holder 32, a plurality of binding portions 56 are provided on the side surfaces facing each other, and a wire for supporting the lens holder 32 is connected to the binding portions 56. Furthermore, a coil 54 for driving the lens holder 32 is wound around the front side of the lens holder 32 in the drawing.

Referring to FIG. 4B, in the present embodiment, the objective lens 40 is fixed to the upper surface around the opening of the lens holder 32, whereby the lens portion 42 of the objective lens 40 is fixed to the opening of the lens holder 32. Is placed.

The lower surface (first main surface) of the flange portion 44 of the objective lens 40 is in contact with the upper surface around the opening of the lens holder 32, and the fixing material 60 adheres to the upper surface of the lens holder 32 and the side surface of the flange portion 44. The objective lens 40 is fixed to the lens holder 32.

Here, as described above, the outer peripheral side surface of the flange portion 44 of the objective lens 40 is the inclined surface 46. Therefore, compared with the case where the outer peripheral side surface is a vertical surface, the bonding strength between the objective lens 40 and the lens holder 32 is improved because the area where the bonding material 60 and the inclined surface 46 are in close contact is large. Furthermore, when the adhesive material 60 is supplied to the side surface of the objective lens 40 and the lens holder 32 by the dispenser in the manufacturing process, the side surface of the flange portion 44 is the inclined surface 46, so the dispenser is applied without contacting the flange portion 44 can do. Furthermore, by preventing the contact or the like of the dispenser in this manner, it is possible to prevent the sticking material 60 from adhering to the upper surface of the flange portion 44 and occurrence of a defect.

The protective portion 58 is provided in a frame shape so as to surround the objective lens 40, and the upper end portion of the protective portion 58 is disposed above the upper end portion of the objective lens 40. Therefore, the protective portion 58 prevents the contact of the objective lens 40 with other members (for example, the surface of the optical disk) under use conditions. Further, as a material of the protective portion 58, a resin material softer than the material of the lens holder 32 is employed. Here, the protective portion 58 has a substantially rectangular shape, but a circular shape may be employed.

Referring to FIG. 4C, here, the side surface located at the opening of the lens holder 32 is formed as an inclined gonio surface 62 (inclined surface), and the flange portion of the objective lens 40 is formed on the gonio surface 62. The lower end of the outer peripheral portion 44 is in contact. In this case, after the objective lens is brought into contact with the gonio surface 62 of the lens holder 32, the relative positional relationship between the objective lens 40 and the lens holder 32 is determined while vibrating the lens holder 32. Here, the first main surface is horizontal. Thereafter, the fixing material 60 is applied to both the inclined surface 46 of the objective lens and the lens holder 32 and solidified to fix the objective lens 40 to the lens holder 32. Even in such a case, when the side surface of the flange portion 44 is the inclined surface 46, the same effect as described above can be obtained. In particular, since the gonio surface and the side surface of the flange are inclined, the moving area of the dispenser is secured, and since the V-shaped groove is formed, the anchor effect can also be expected.

FIGS. 4 (D) and (E) are FIGS. 1 (A) and 1 (B) of the original application. Since this is a conceptual drawing, it has been described using FIG. 4 (B) as a specific example of FIG. 4 (D), and the specific example of FIG. 4 (E) has been described using FIG. 4 (C).

Another form of the lens holder 32 will be described with reference to FIG. Here, on the upper surface of the lens holder 32, a groove 66 is provided which extends from the edge of the circular opening 64 to the periphery. The groove 66 is for supplying a liquid fixing material to the objective lens in the manufacturing process, and in consideration of the weight balance of the lens holder 32, the groove 66 is symmetrical with respect to the center of the opening 64. It is provided. In the method of using the groove 66, after the objective lens is placed on the upper surface of the lens holder 32 so as to close the opening 64, the fixing material is supplied to the objective lens via the groove 66. This prevents contact between the dispenser and the objective lens since the tip of the dispenser does not have to be close to the objective lens.

A method of manufacturing the above-described objective lens by injection molding will be described with reference to FIG. FIG. 6 (A) is a plan view showing an outline of a mold 70 used, FIG. 6 (B) is a cross-sectional view thereof, and FIG. 6 (C) is a cross-sectional view showing a collimated lens to be formed. .

Referring to FIG. 6A, the mold 70 used in this step is in communication with the plurality of cavities 72 arranged in a matrix (2 rows × X columns: X is an integer) and the plurality of cavities 72. A runner 74 is provided.

The individual cavities 72 have the same shape as the objective lens 40 shown in FIG. The runners 74 are elongated paths through which the liquid resin material supplied to the respective cavities passes, and are in communication with the respective cavities 72.

In this step, first, referring to FIG. 6A, the resin material as the material of the objective lens is heated and melted to make it liquid or semisolid, and the resin material is supplied to each cavity 72 via the runner 74. Do. In the figure, the path through which the molten resin material passes is indicated by an arrow. After all the cavities 72 are filled with the resin material, the filled resin material is cured to take out each objective lens 40 made of the cured resin material from the mold 70.

Referring to FIG. 6B, the shape of the inner wall of each cavity 72 has a shape corresponding to the lens portion 42 and the flange portion 44 of the objective lens 40. Further, the side surface of each cavity 72 has a shape conforming to the inclined surface 46 and the concave region 50 shown in FIG. 3 (B). Furthermore, the runner 74 is connected to a portion corresponding to the inclined surface facing the concave area 50 of the objective lens 40. In this figure, the contact surface on which the upper mold and the lower mold constituting the mold 70 are in contact is shown by a dotted line. The contact surface may be disposed at the lower end of the inclined surface 46 or may be disposed in the middle of the inclined surface 46.

FIG. 6C partially shows the objective lens 40 in a state of being taken out of the mold 70. As shown in this figure, the respective objective lenses 40 are connected by a runner portion 76 made of a resin material filled in the runner 74.

In order to separate each objective lens 40, it is necessary to cut off the runner 76 and the objective lens 40. In the conventional lens forming method, both are cut and separated at the boundary between the runner portion 76 and the objective lens 40, but in the present embodiment, the runner portion 76 is cut at the intermediate portion. In the figure, the location where the runner portion 76 is to be cut off is shown by a dotted line, and is located inside the end of the flange portion 44, that is, inside the concave region 50.

If this cut portion is provided at the boundary between the objective lens 40 and the runner portion 76, the stress caused by the cut may cause aberration in the objective lens 40, which may deteriorate the reading accuracy and the writing accuracy. In addition, when the cut portion is disposed outside the outer edge of the flange portion 44, although the problem of the aberration deterioration is alleviated, the remaining portion of the runner portion 76 protrudes outward as a projection portion, and the use condition or manufacturing process As a result, the projection may collide with another member. Therefore, in the present embodiment, the cut portion of the runner portion 76 is set such that the remaining portion of the runner portion 76 is disposed inside the outer peripheral edge portion of the flange portion 44. Thereby, the remaining part of the runner part 76 becomes a part of objective lens 40 as the protrusion part 52 shown to FIG. 3 (A).

Alternatively, a plurality of cavities 72 may be connected via the runner 74 inside the mold 70 by adopting FIG. 6 (D). As a result, runners 76 shown in FIG. 6C are formed on both sides of the objective lens 40, and protrusions 52 shown in FIG. 3B are formed on both sides. Furthermore, a concave area 50 shown in FIG. 6C may be provided at the opposite end of the objective lens 40, and a runner portion 76 may be formed inside the concave area 50.

The objective lens 40 manufactured by the above-described process is fixed to the lens holder by being coated with the fixing material 60 after being mounted on a predetermined place of the lens holder 32, as shown in FIG. Further, the lens holder 32 provided with the objective lens 40 is accommodated in the housing 12 together with the other optical elements shown in FIG.

DESCRIPTION OF SYMBOLS 10 Optical pick-up apparatus 12 Housing 14 Laser unit 16 Diffraction grating 18 Photodetector 22 Half mirror 24 1⁄4 wavelength plate 26 Collimator lens 28 Objective lens drive device 32 Lens holder 34 Engage part 36 Insertion part 38 Disc 40 Objective lens 42 Lens Portion 44 Flange portion 45 First main surface 46 Slope surface 46 A Slope surface 47 Second main surface 48 Step portion 50 Concave region 52 Projection portion 54 Coil 56 Tangled portion 58 Protective portion 60 Fixing material 62 Gonio face 64 Opening portion 66 Groove 70 Mold 72 Cavity 74 Runner 76 Runner

Claims

An objective lens for condensing laser light on an information recording layer of an optical disc, and a lens holder to which the objective lens is fixed,
The objective lens includes a lens portion through which the laser beam passes, a flange portion surrounding the lens portion, a first main surface of the flange portion facing the lens holder, and a second surface facing the first main surface. A main surface, and a side surface connecting the first main surface and the second main surface,
An outer peripheral end of the second main surface of the flange portion is positioned inward of an outer peripheral end of the first main surface;
An optical pickup device characterized in that the objective lens is fixed to the lens holder by a fixing material in contact with the side surface of the objective lens and the surface of the lens holder.
The optical pickup device according to claim 1, wherein the side surface of the flange portion is an inclined surface.
The optical pickup device according to claim 1, wherein the side surface of the flange portion has a step shape.
A protective unit attached to the lens holder so as to surround the objective lens;
The optical pickup device according to any one of claims 1 to 3, wherein an end portion of the protective portion protrudes more than an end portion of the flange portion.
It has a projection which protrudes outside continuously from a part of the side of the flange,
The optical pickup device according to any one of claims 1 to 4, wherein an end of the protrusion is disposed inside the outer peripheral edge of the first main surface.
A lens portion through which laser light is transmitted, a flange portion integrally formed so as to surround the lens portion, a first main surface of the flange portion, a second main surface facing the first main surface, and It has a side surface that connects one main surface and the second main surface,
An objective lens characterized in that an outer peripheral end of the second main surface of the flange portion is disposed inward of an outer peripheral end of the first main surface.