JP2011108303A - Optical element and optical pickup device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thin objective lens that is reliably manufactured, and also to provide an optical pickup device using the same. <P>SOLUTION: The optical element that is a biconvex lens made of glass materials includes: a lens having a first optical surface which laser beams enter and a second optical surface from which the incident laser beams is emitted; and a peripheral section arranged at the periphery of the lens with at least part of the peripheral section optically axially projecting beyond the second optical surface, which is composed of a first peripheral surface arranged at the first optical surface side and a second peripheral surface arranged at the second optical surface side, with a curved connection of the second optical surface and the second peripheral surface. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an optical element and an optical pickup device using the optical element.

  In recent years, high-density optical discs such as Blu-ray Disc (registered trademark; hereinafter also referred to as BD) optical pickup devices are also used in conventional optical discs such as CD (Compact Disc (registered trademark)), DVD ( Similar to an optical pickup device for an optical disk such as Digital Versatile Disc (registered trademark), there is a demand for thinning the entire device. The reduction in size and thickness of the optical pickup device contributes to the reduction in size and thickness of products equipped with this optical pickup device. Further, as the optical pickup device is reduced in size and thickness, the types of products on which the optical pickup device can be mounted increase. Therefore, due to the mass production effect of the optical pickup device and the optical member used therefor, the cost of the optical pickup device and the optical member used therefor can be reduced.

  An objective lens is one of the optical components having a large influence on the thickness of the optical pickup device. Due to the optical arrangement, the thickness of the objective lens affects the thickness of the optical pickup device. Therefore, it is necessary to reduce the thickness of the objective lens in order to reduce the thickness of the optical pickup device.

  In the case of an objective lens for BD, the lens thickness tends to be thick because correction of off-axis aberrations and the like is performed in a high NA range. The term “thick lens thickness” as used herein refers to the thickness on the lens axis when normalized by the focal length, and indicates that the thickness is thicker than a relatively low NA objective lens for CD and DVD. Here, the description will focus on a biconvex single lens that is superior in terms of optical performance and cost.

  In the lens design, since the objective lens optical surface on the light source side needs to bend the incident light largely, it is generally a high power surface and the amount of sag tends to increase.

  In addition, since the optical surface of the objective lens on the disk side also has a convex power, the lens thickness decreases toward the periphery. Here, the optical surface includes a refracting surface such as an aspherical surface, a diffractive surface, and a phase step surface.

  When the lens thickness is made as thin as possible, the edge thickness may not be secured in the vicinity of the lens effective diameter and the outer periphery thereof. As a result, cracking occurs when the lens is molded or when the lens is attached to the optical pickup.

  Therefore, a measure to prevent the lens from cracking can be considered by securing a certain edge thickness.

  For example, in Patent Documents 1, 2, and 3, a high NA objective lens includes a resin objective lens in which a region having a thicker thickness in the optical axis direction is provided on the outer peripheral portion than a thickness in the optical axis direction in an effective diameter region. It is disclosed.

JP 2007-334928 A JP 2007-334929 A JP 2007-334930 A

  FIG. 5 is a side view when the configuration of the above-mentioned patent document is applied to a glass lens.

  In the optical element 80 to which the configuration disclosed in the above patent document is applied, the optical surface 81 and the outer peripheral surface 82 are connected by a discontinuous surface. The configuration as in the above-mentioned patent document has no problem in the case of a lens made of resin, but when applied to a lens made of glass, there arises a problem that a crack 83 occurs at the connection portion between the optical surface 81 and the outer peripheral surface 82. It was. Specifically, cracking occurred when the lens was molded or when the lens was attached to the optical pickup.

  Therefore, the configuration disclosed in the above patent document cannot be applied to a lens made of glass. The reason is considered to be caused by a difference between a resin lens construction method (for example, injection molding) and a glass lens construction method (for example, lens molding).

  In view of the above problems, an object of the present invention is to provide a thin lens in a glass lens that is less likely to crack during lens molding or lens mounting.

  In order to achieve the above object, an optical element according to the present invention is a biconvex optical element made of a glass material, and includes a first optical surface on which laser light is incident and a second optical surface on which the incident light is emitted. An optical surface; and an outer peripheral portion provided on an outer periphery of the lens portion, wherein at least a part protrudes in an optical axis direction from the second optical surface, and the outer peripheral portion includes the first optical surface. A first outer peripheral surface provided on the first optical surface side and a second outer peripheral surface provided on the second optical surface side, and a connecting portion between the second optical surface and the second outer peripheral surface is It has a configuration that forms a curved surface.

  ADVANTAGE OF THE INVENTION According to this invention, in the lens which consists of glass, the thin lens which is hard to generate | occur | produce the crack at the time of lens shaping | molding or lens attachment can be provided.

1 is a side view showing a schematic configuration of an optical element according to Embodiment 1. FIG. A side view showing a schematic configuration of an optical element according to Embodiment 2. A side view showing a schematic configuration of an optical element according to Embodiment 3. The figure which shows schematic structure of the optical pick-up apparatus which concerns on Embodiment 4. FIG. The side view which shows schematic structure of the optical element which adapted the structure of patent documents 1-3 to the glass lens

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that in the embodiments, components that perform similar operations or components that have similar functions are denoted by the same reference numerals, and description thereof may not be repeated.

(Embodiment 1)
FIG. 1 is a side view showing a schematic configuration of an optical element 10 according to the first embodiment.

  The optical element 10 according to the present embodiment is an objective lens made of a glass material. The optical element 10 is mounted on the optical pickup device 100 as shown in FIG. 4, for example, and focuses the laser beam 110 on the information recording surface of the information recording medium 50.

  Here, the type of the information recording medium 50 is not particularly limited. The information recording medium 50 may be, for example, a CD (Compact Disc Rerecordable), a CD-RW (Compact Disk Read Only Memory), a CD-ROM (Compact Disk Read Only Memory), a DVD (Digit Discrete Memory), or a DVD (Digit Digital Memory). DVD-R (Digital Versatile Disc Recordable), DVD-RW (Digital Versatile Disc Rewriteable), DVD-ROM (Digital Versatile Disc Read Only Memory), DVD-ROM (Digital Versatile Disc Read Only Memory), DVD-ROM (Digital Versatile Disc Rewriteable Memory) EVD (Enhanced Versatile Disc), EVD-R (Enhanced Versatile Disc Recordable), EVD-RW (Enhanced Versatile Disc ReWritable), EVD-ROM (Enhanced Versatile Disc Read Only Memory), EVD-RAM (Enhanced Versatile Disk Random Access Memory) BD (Blu-ray Disc Read Only Memory), BD-R (Blu-ray Disc Recordable), BD-RW (Blu-ray Disc Rewritable), BD-ROM (Blu-ray Disc Read Only Memory), BD-RAM lu-ray Disc Random Access Memory), HD-DVD (High Definition Digital Versatile Disc), HD-DVD-R (High Definition Digital Versatile Disc Recordable), HD-DVD-RW (High Definition Digital Versatile Disc ReWritable), HD- DVD-ROM (High Definition Digital Versatile Disc Read Only Memory), HD-DVD-RAM (High Definition Digital Versatile Disc Access Memory, etc.) Disk (or more, all registered trademark) may be.

  Hereinafter, the present embodiment will be described with reference to FIG.

  Laser light 60 having a wavelength of 408 nm emitted from a light source (not shown) is made into substantially parallel light by a collimating lens (not shown) or the like and enters the optical element 10. The optical element 10 is a single lens composed of two different aspherical surfaces made of a glass material and having a positive power. The laser beam 60 is incident on the aspherical first optical surface 21 and is emitted from the aspherical second optical surface 22. The emitted laser beam 60 is focused by the optical element 10 to form a good spot on the information recording surface of the optical information recording medium 50. The laser beam 60 reflected on the optical information recording surface enters from the second optical surface 22, exits from the first optical surface 21, enters the collimating lens or the like again as substantially parallel light, and the detector (FIG. (Not shown) and converted into an electrical signal and detected as a signal.

  Hereinafter, the configuration and shape of the optical element 10 will be described in detail.

  The optical element 10 is made of a glass material. The glass material used for the optical element 10 can be appropriately selected according to the characteristics required for the optical element 10. The glass transition point of the glass material is, for example, 400 degrees or more.

  The optical element 10 includes a lens portion 20 and an outer peripheral portion 30 provided on the outer periphery of the lens portion 20. The lens unit 20 includes a first optical surface 21 and a second optical surface 22. The outer peripheral portion 30 has a first outer peripheral surface 31 and a second outer peripheral surface 32.

  The lens unit 20 is formed so that the thickness in the optical axis direction becomes thinner from the optical axis 70 in the radial direction. That is, the distance between the first optical surface 21 and the second optical surface 22 decreases as the distance from the optical axis 70 increases in the radial direction. Here, in the present specification, a portion of the first optical surface 21 that is closest to the second optical surface 22 side is defined as an end portion of the first optical surface 21. Further, a portion of the second optical surface 22 that is closest to the first optical surface 21 is defined as an end portion of the second optical surface 22.

  The outer peripheral portion 30 formed outside the lens portion 20 is formed so that the thickness in the optical axis direction increases as the distance from the optical axis 70 increases.

  The first optical surface 21 is a convex surface having an optical function. Here, the optical function refers to a function for producing optical characteristics required for the optical element 10.

  The second optical surface 22 is a convex surface having an optical function. The second optical surface 22 is disposed at a position facing the first optical surface.

  Each of the first optical surface 21 and the second optical surface 22 has a region corresponding to an optical effective diameter that is a diameter when the actual laser beam 60 passes. The optical effective diameter of the first optical surface 21 is the length of a line segment connecting the intersections of the laser beam 60 and the first optical surface 21. The optical effective diameter of the second optical surface 22 is the length of a line segment connecting the intersections of the second optical surface 22 and the laser beam 60.

  The first outer peripheral surface 31 is provided on the first optical surface 21 side. The first outer peripheral surface 31 is provided on the outer periphery of the first optical surface 21.

  The second outer peripheral surface 32 is provided on the second optical surface 22 side. The second outer peripheral surface 32 is provided on the outer periphery of the second optical surface 22. Further, at least a part of the second outer peripheral surface 32 protrudes more in the optical axis direction than the second optical surface 22. The protruding surface is formed perpendicular to the optical axis. With such a configuration, the thickness of the outer peripheral portion 30 can be ensured.

  A connecting portion between the second optical surface 22 and the second outer peripheral surface 32 is formed as a concave curved surface 41. The curved surface 41 is formed by continuously connecting the end of the second optical surface 22 and the end of the second outer peripheral surface 32. In other words, the second optical surface 22 and the second outer peripheral surface 32 are smoothly connected.

  With such a configuration, it is possible to prevent cracks that have occurred in conventional optical elements.

  In the conventional optical element, the connection portion between the optical surface and the outer peripheral surface is formed as a discontinuous surface. For this reason, it is considered that stress was concentrated on the connecting portion during lens molding or lens mounting, and cracking occurred. Moreover, since this connection part is the part where the thickness in the optical axis direction is the thinnest, it is considered that the connection part was particularly easily broken.

  On the other hand, in the present embodiment, the connection portion between the second optical surface 22 and the second outer peripheral surface 32 is formed by a curved surface 41. In other words, the end of the second optical surface 22 and the end of the second outer peripheral surface 32 are connected continuously. In other words, the second optical surface 22 and the second outer peripheral surface 32 are smoothly connected. Therefore, it is considered that the stress concentration generated in the conventional optical element is relaxed and cracking is prevented.

  Since the optical element 10 according to the present embodiment has the above-described configuration, it is difficult for cracks to occur during lens molding. Therefore, the optical element 10 can be molded stably.

  Further, the optical element 10 has a sufficient thickness of the outer peripheral portion 30, and the connecting portion where the thickness in the optical axis direction is the smallest is also formed by the curved surface 41. For this reason, it is possible to prevent cracking when the optical pickup device is attached.

  Further, the radius of curvature of the curved surface 41 is formed to be smaller than the radius of curvature of the second optical surface 22. With such a configuration, the outer peripheral surface 32 starts to protrude in the optical axis direction at a position closer to the optical axis. As a result, a thick portion of the outer peripheral portion 30 can be secured widely. Therefore, it is possible to further prevent cracking when mounting the optical pickup device.

  The curved surface 41 is preferably formed closer to the optical axis than the connection portion between the first optical surface 21 and the first outer peripheral surface 31. If the curved surface 41 and the connecting portion are located on the same axis parallel to the optical axis, or if the curved surface 41 is further away from the optical axis than the connecting portion, the lens portion 20 and the outer peripheral portion 30 The connecting portion becomes very thin and the portion is easily broken. On the other hand, by forming the curved surface 41 at a position where the connecting portion is also close to the optical axis, it becomes easy to ensure the thickness of the connecting portion. By adopting such a configuration, it becomes easier to prevent cracks during molding of the lens and cracks when attached to the optical pickup device.

  In the present embodiment, the optical element 10 is composed of two aspheric surfaces, but is not limited thereto. For example, it may be a diffractive surface or a phase step surface.

  Moreover, in this embodiment, although the optical element 10 is comprised mainly by glass, it is not restricted to this. For example, a close-contact laminated composite optical element in which an optical element made of resin is laminated on an optical element made of glass may be used. In the case of a close-contact laminated composite optical element, the interface may be an aspherical surface, a spherical surface, a diffractive surface, a phase step surface, or the like.

(Embodiment 2)
FIG. 2 is a side view showing a schematic configuration of the optical element 11 according to the second embodiment.

  The optical element 11 according to the second embodiment is different from the optical element 10 according to the first embodiment in that the outer peripheral portion 30 further has a curved surface 42.

  In the present embodiment, the second outer peripheral surface 32 has a projecting surface 33 projecting in the optical axis direction from the second optical surface 22, and an intermediate surface 34 provided on the optical axis side from the projecting surface 33. A connecting portion between the projecting surface 33 and the intermediate surface 34 is formed as a convex curved surface 42. The curved surface 42 is formed by continuously connecting the end of the protruding surface 33 and the end of the intermediate surface 34. In other words, the protruding surface 33 and the intermediate surface 34 are smoothly connected. That is, in the optical element 11 according to Embodiment 2, the center from the optical axis center of the second optical surface 22 to the outermost peripheral end portion of the second outer peripheral surface 32 is a continuous surface.

  With such a configuration, it is possible to prevent not only the crack of the connection portion between the second optical surface 22 and the second outer peripheral surface 32 but also the crack of the connection portion between the protruding surface 33 and the intermediate surface 34. As a result, cracks during lens molding are further less likely to occur. Therefore, the optical element 11 can be molded more stably.

  The curvature radius of the curved surface 42 is preferably formed to be larger than the curvature radius of the curved surface 41. With such a configuration, processing of the mold corresponding to the outer peripheral portion 30 is facilitated. As a result, productivity in lens molding can be improved.

(Embodiment 3)
FIG. 3 is a side view showing a schematic configuration of the optical element 12 according to the third embodiment.

  The optical element 12 according to the third embodiment is different from the optical elements according to the other embodiments in that a connecting portion between the first optical surface 21 and the first outer peripheral surface 31 is formed as a curved surface 43.

  The curved surface 43 is formed in a concave shape.

  The curved surface 43 is formed by continuously connecting the end portion of the first optical surface 21 and the end portion of the first outer peripheral surface 31. In other words, the first optical surface 21 and the first outer peripheral surface 31 are smoothly connected. That is, the optical element 12 according to Embodiment 3 is a surface having continuity from the center of the optical axis of the first optical surface 21 to the outermost peripheral end portion of the first outer peripheral surface 31.

  With such a configuration, it is possible to prevent not only the crack on the second optical surface side but also the crack at the connection portion between the first optical surface 21 and the first outer peripheral surface 31. As a result, cracks during lens molding are further less likely to occur. Therefore, the optical element 12 can be molded more stably.

  The curved surface 41 is preferably formed at a position closer to the optical axis than the curved surface 43. If the curved surface 41 and the curved surface 43 are located on an axis parallel to the optical axis, or if the curved surface 41 is farther from the optical axis than the curved surface 43, the connecting portion between the lens portion 20 and the outer peripheral portion 30 is It becomes very thin and the part becomes easy to break. On the other hand, by forming the curved surface 41 at a position closer to the optical axis than the curved surface 43, it becomes easy to ensure the thickness of the connection portion. By adopting such a configuration, it becomes easier to prevent cracks during molding of the lens and cracks when attached to the optical pickup device.

(Embodiment 4)
FIG. 4 is a diagram illustrating a schematic configuration of the optical pickup device according to the fourth embodiment.

  The optical pickup device 100 according to the present embodiment includes the thin optical element described in the first to third embodiments. Thereby, a thin optical pickup device capable of performing stable recording and reproduction can be realized.

  An optical pickup device 100 according to this embodiment includes a light source 101, a beam shaping lens 104, a beam splitter 105, a collimator lens 102, a rising mirror 107, an objective lens 103, a detection lens 108, and a detector 109. With.

  The light source 101 emits a laser beam 110 having a wavelength corresponding to the type of the information recording medium 106. In the present embodiment, the laser light 110 emitted from the light source 101 is divergent light. For example, when the information recording medium 106 is BD (registered trademark), the light source 101 emits laser light having a wavelength of 378 to 438 nm (may be less than 420 nm). On the other hand, when the information recording medium 106 is a DVD (registered trademark), the light source 101 emits laser light having a wavelength of 630 to 690 nm. When the information recording medium 106 is a CD (registered trademark), the light source 101 emits laser light having a wavelength of 750 to 810 nm. Further, for example, when the optical pickup device is for focusing laser light on three types of optical discs of CD, DVD, and BD, the light source 101 corresponds to the type of the optical disc arranged with respect to the optical pickup device. The light of wavelength is selectively emitted.

  The beam shaping lens 104 is a lens that shapes the laser light emitted from the light source 101 into a desired shape. The beam shaping lens 104 is disposed in front of the light source 101. Laser light shaped by the beam shaping lens 104 enters the beam splitter 105.

  The beam splitter 105 is an optical element that transmits light in one deflection direction and reflects light in the deflection direction orthogonal thereto. The beam splitter 105 reflects the beam shaped by the beam shaping lens 104 toward the collimating lens 102. The laser beam reflected by the information recording medium 106 passes through the beam splitter 105 and enters the detector 109.

  The collimating lens 102 is an optical element that emits light that has entered the collimating lens 102 as substantially parallel light. The substantially parallel light means light in which the laser light 110 does not spread and the diameter of the laser light 110 does not change even when the light travels. The collimating lens 102 may be configured by a single lens or may be configured by a plurality of lenses.

  The rising mirror 107 is an optical element that reflects the laser light that has been collimated by the collimator lens 102 in a direction perpendicular to the recording surface of the information recording medium 106. The laser beam reflected by the rising mirror 107 enters the objective lens 103.

  The objective lens 103 is a lens that condenses the laser light emitted from the light source 101 on the recording surface of the information recording medium 106. In the present embodiment, the objective lens 103 is configured by only one lens, but is not limited thereto. If necessary, it may be configured with one or a plurality of other optical elements such as a phase correction element and a beam expander lens.

  The NA of the objective lens 103 is not particularly limited, but may be, for example, 0.8 or more, particularly when the optical pickup device focuses laser light on BD (registered trademark) or the like. preferable.

  The laser beam focused on the information recording surface of the information recording medium 106 by the objective lens 103 is reflected by the information recording surface. Then, the laser light reflected by the information recording surface passes through the objective lens 103, the rising mirror 107, the collimator lens 102, and the beam splitter 105 again, and is incident on the detector 109 by the detection lens 108. .

  In the present embodiment, the collimator lens 102 has a function as an aberration correction element, and is positioned at a reference position between the beam splitter 105 and the objective lens 103. The collimating lens 102 is configured to be displaceable on the optical axis AX from the reference position. Furthermore, in the present embodiment, the objective lens 103 is configured such that substantially parallel light is incident on the objective lens 103 when the collimating lens 102 as an aberration correction element is located at the reference position.

  Here, the objective lens 103 has the same shape as the optical element 10 shown in FIG. That is, the objective lens 103 is a biconvex lens made of a glass material. The objective lens 103 is a so-called aspherical lens.

  Hereinafter, the surface shape of the exit surface side of the objective lens 103 will be described in detail. Here, the surface on the exit surface side corresponds to the surface constituted by the second optical surface and the second outer peripheral surface of the above-described first to third embodiments.

  The exit surface of the objective lens 103 is a convex aspherical surface having a positive power within the effective diameter. Then, the lens thickness in the optical axis direction becomes thinner as going from the optical axis in the radial direction. That is, the sag amount on the exit surface decreases. Here, the sag amount represents the amount of displacement in the direction of the optical axis when a plane that passes through the intersection of the exit surface and the optical axis and is perpendicular to the optical axis is used as a reference plane. The sign of the sag amount on the exit surface is negative on the light source side and positive on the information recording medium side.

  In the outer peripheral region exceeding the effective diameter, the outer peripheral surface is connected to the outer peripheral surface by a curved surface different from the aspherical surface of the effective inner diameter region, and the lens thickness increases in the optical axis direction. That is, the sag amount on the exit surface decreases from the optical axis to the effective diameter, but reverses and increases in the vicinity of the effective diameter. Then, when a part of the outer peripheral surface protrudes in the optical axis direction from the optical surface, the sag amount is reversed to plus. By setting it as such a shape, the crack at the time of lens shaping | molding can be prevented, and lens shaping | molding can be performed easily. Further, it is possible to prevent cracking when the objective lens 103 is attached to a lens holder (not shown).

  In the present embodiment, the case where the collimator lens 102 is used as an aberration correction element has been described as an example. However, the aberration correction element may be a single beam expander lens disposed between the collimator lens and the objective lens, or You may comprise by a beam expander lens and a collimating lens. Further, a liquid crystal lens, a liquid lens, or the like may be used as the aberration correction element.

  Further, in the present embodiment, the optical element such as a lens other than the objective lens may be configured by only a refractive surface having substantially only a refractive action, and other elements such as a diffraction surface and a phase step surface. It may have an optical function surface.

  The optical pickup device 100 may further include an element that does not substantially affect the transmitted wavefront aberration between the light source 101 and the information recording medium 106.

  In the present embodiment, the BD optical system has been described, but an actuator (not shown) on which the objective lens 103 is mounted is further provided with an objective lens so that DVD, CD, etc. can be recorded and reproduced by the same optical pickup device. A so-called two-lens configuration may be used.

  Hereinafter, examples of the objective lens 103 will be specifically described. The objective lens according to the present example has the same shape as the optical element 11 according to the second embodiment described above.

  The objective lens 103 according to the example is designed with a design wavelength of 406 nm, a focal length of 0.9 mm, a numerical aperture (NA) of 0.85, and an information recording medium protective layer thickness of 0.085 mm. Here, the thickness of the designed protective layer is set to 0.085 mm in order to cope with a BD multilayer disc, and the protective layer thickness from the surface to the recording surface is between the thickest layer and the thinnest layer. This is because of the design.

  In addition, a curved surface 41 and a curved surface 42 are formed on the emission surface. The curvature radius R1 of the curved surface 41 was set to 0.09 mm, and the curvature radius R2 of the curved surface 42 was set to 0.45 mm. Further, the thickness of the outer peripheral portion 30 in the optical axis direction was 220 μm.

  When such an objective lens 103 was produced by lens molding, a lens without cracks could be molded.

  The objective lens according to the present invention can obtain a lens shape that can be stably manufactured even if it is a thin objective lens. Therefore, a CD (Compact Disc), a DVD (Digital Versatile Disc), and a BD (Blu- For example, information devices such as computers, video devices, and audio devices that perform recording and reproduction on various information recording media such as ray discs, EVDs (Enhanced Versatile Discs), and HD-DVDs (High Definition Digital Versatile Discs) Etc. are useful.

DESCRIPTION OF SYMBOLS 10, 11, 12 Optical element 20 Lens part 21 1st optical surface 22 2nd optical surface 30 Outer peripheral part 31 1st outer peripheral surface 32 2nd outer peripheral surface 33 Projection surface 34 Intermediate | middle surface 41, 42, 43 Curved surface 50 Information recording medium 60 Laser beam 70 Optical axis 80 Optical element 81 Optical surface 82 Outer peripheral surface 83 Cracking 100 Optical pickup device 101 Light source 102 Collimating lens 103 Objective lens 104 Beam shaping lens 105 Beam splitter 106 Information recording medium 107 Rising mirror 108 Detection lens 109 Detector 110 Laser light

Claims (9)

A biconvex optical element made of a glass material,
A lens unit having a first optical surface on which laser light is incident and a second optical surface on which the incident light is emitted;
An outer peripheral portion provided on an outer periphery of the lens portion, at least a part of which protrudes in the optical axis direction from the second optical surface;
With
The outer periphery is
A first outer peripheral surface provided on the first optical surface side;
A second outer peripheral surface provided on the second optical surface side,
A connecting portion between the second optical surface and the second outer peripheral surface forms a curved surface;
Optical element. The curved surface connecting the second lens surface and the second outer peripheral surface is a concave surface.
The optical element according to claim 1. The radius of curvature of the curved surface is smaller than the radius of curvature of the second optical surface;
The optical element according to claim 1. The second outer peripheral surface has a protruding surface provided at a position protruding in the optical axis direction from the emission surface, and an intermediate surface provided on the optical axis side of the protruding surface,
A connecting portion between the projecting surface and the intermediate surface forms a curved surface;
The optical element according to claim 1. The curved surface connecting the projecting surface and the intermediate surface is a convex surface.
The optical element according to claim 4. A curvature radius of a curved surface connecting the projecting surface and the intermediate surface is larger than a curvature radius of a curved surface connecting the second lens surface and the second outer peripheral surface;
The optical element according to claim 4. A connecting portion between the first lens surface and the first outer peripheral surface is formed as a curved surface,
The optical element according to claim 1. The position of the curved surface connecting the second lens surface and the second outer peripheral surface is closer to the optical axis than the position of the curved surface connecting the first lens surface and the first outer peripheral surface.
The optical element according to claim 7. An optical pickup device comprising the optical element according to claim 1.

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