JP5050938B2 - Optical element, optical head, and optical recording apparatus - Google Patents

Description

  The present invention relates to an optical element, an optical head, and an optical recording apparatus.

  In the magnetic recording method, when the recording density increases, the magnetic bit is significantly affected by the external temperature and the like. For this reason, a recording medium having a high coercive force is required. However, when such a recording medium is used, the magnetic field required for recording also increases. The upper limit of the magnetic field generated by the recording head is determined by the saturation magnetic flux density, but its value approaches the material limit and cannot be expected to increase dramatically. Therefore, a method of guaranteeing the stability of the recorded magnetic bit by locally heating at the time of recording, causing magnetic softening, recording with a reduced coercive force, and then stopping the heating and naturally cooling Has been proposed. This method is called a heat-assisted magnetic recording method.

  In the heat-assisted magnetic recording method, it is desirable to instantaneously heat the recording medium. Further, the heating mechanism and the recording medium are not allowed to contact each other. For this reason, heating is generally performed using absorption of light, and a method of using light for heating is called a light assist type. When ultra-high-density recording is performed by the optical assist method, the required light spot diameter is about 20 nm. However, in a normal optical system, light cannot be condensed to that extent due to the diffraction limit.

  Therefore, an optical head using near-field light (also referred to as near-field light) generated from an optical aperture having a size equal to or smaller than the incident light wavelength is used.

As an example of the optical head, there is a near-field optical head including a mirror substrate, an aperture substrate, and an optical fiber (see Patent Document 1). The mirror substrate is made of Si, has a slope, and has a mirror surface on which Al is deposited. Further, a V-groove is formed in the mirror substrate, and an optical fiber is fixedly bonded to the V-groove. The aperture substrate is made of SiO ₂ and has a micro lens on the top surface, a slider for air levitation on the bottom surface, and a near-field light generating microstructure between them. The tip of the near-field light generating microstructure is located on a plane defined by the bottom surface of the slider. The light emitted from the optical fiber is bent by approximately 90 ° on the mirror surface and reflected, enters the microlens, is collected by this lens, and is applied to the near-field light generating microstructure.
JP 2003-6913 A

  FIG. 9 shows an optical head 300 as an example of a conventional optical head. The optical head 300 includes an optical element 101 and a slider 15. FIG. 9A is a side view of the optical head 300, and FIG. 9B is a perspective view of the optical element 101 constituting the optical head 300 as viewed from the bottom surface side (side facing the top surface of the slider 15). The optical element 101 includes a V-groove 24, and an optical fiber 11 that guides light from a light source (not shown) is fixed to the V-groove 24. The light OP emitted from the optical fiber 11 enters the optical element 101, is deflected by the deflection surface 22, and is emitted from the bottom surface 27 facing the slider 15. The emitted light is guided by the optical waveguide 16 provided in the slider 15 and emitted toward the disk 2 as a recording medium. A minute metal structure (not shown) that generates near-field light is provided on the exit surface of the optical waveguide 16.

  In order to perform good recording on the disc 2, it is necessary to collect the light spot emitted toward the disc 2 with a sufficiently small diameter and to obtain a sufficient light intensity of the light spot. Condensing the light spot with a sufficiently small diameter can be achieved by providing the above-described minute metal structure in the vicinity of the exit surface of the optical waveguide 16. On the other hand, in order to obtain sufficient light intensity, for example, it is conceivable to increase the light power of the light source. However, it is necessary to increase resistance to heat generated when the light power of the light source is increased. The structure of the optical transmission system including the size will increase. For this reason, in order to reduce the size of the optical head and the like while ensuring sufficient light intensity applied to the disk 2, the light transmission system from the light source to the disk 2 can efficiently transmit light so as not to cause light loss as much as possible. It is important to guide

  However, the optical head 300 is fixed by sandwiching the adhesive layer 103 between the optical element 101 and the slider 15, and bubbles mixed into the adhesive layer 103 on the optical path or the adhesive layer 103 and the optical element are optically coupled. There has been a problem that light loss occurs due to Fresnel reflection caused by the difference in refractive index between the materials of the element 101 and the optical waveguide 16.

  Further, since the adhesive layer 103 is provided in the gap between the optical element 101 and the slider 15 and the optical element 101 and the slider 15 are fixed without being in direct contact with each other, the non-uniform thickness of the adhesive layer 103 causes the slider 15 to be fixed. In some cases, the optical element 101 mounted on the optical system 101 is inclined. In this case, the light emitted from the optical element 101 is incident on the incident surface of the optical waveguide 16 with an inclination, so that the optical coupling efficiency is reduced and light loss occurs. Further, the non-uniform thickness of the adhesive layer 103 may cause peeling due to stress concentration.

  In the near-field optical head of Patent Document 1, the configuration is similar to that of the optical head 300, but no reference is made to the coupling between the mirror substrate (corresponding to the optical element 101) and the aperture substrate (corresponding to the slider 15).

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide an optical element that can be coupled to a light transmitting portion with low optical loss and with high optical coupling efficiency, and an optical head including this optical element. And a recording apparatus including an optical head.

  Said subject is solved by the following structures.

1. An optical element that is mounted on a base member having a light transmission part and guides light from a light source to the light transmission part,
An optical element, wherein a convex portion that is in contact with the base member and transmits light from the light source is provided on a surface facing the base member, and a tip of the convex portion is flat.

  2. 2. The optical element according to 1, wherein the optical element includes a convex portion whose tip is in contact with two or more base members including a convex portion having a flat tip.

  3. 3. The optical element according to 1 or 2, wherein the material of the optical element is a thermoplastic resin.

  4). The optical element according to any one of claims 1 to 3, further comprising a deflecting unit that deflects light from the light source toward the light transmitting unit.

  5). 5. The optical element according to 4, further comprising a V-groove for arranging a linear light guide for guiding the light to the deflecting unit.

6). A base member having a light transmission part;
An optical head comprising: the optical element according to any one of 1 to 5.

  7). 7. The optical head according to 6, wherein an adhesive layer made of a material having a refractive index smaller than the refractive index of the material of the optical element is provided in a gap between the base member and the optical element.

  8). An optical recording apparatus comprising the optical head according to 6 or 7.

  According to the optical element of the present invention, it is possible to efficiently couple with the light transmission part while suppressing light loss. In addition, according to the optical head and the optical recording apparatus of the present invention, it is possible to provide an optical element that can be coupled to the light transmitting portion with low optical loss and with high optical coupling efficiency.

  Hereinafter, the present invention will be described based on an optically assisted magnetic recording head having a magnetic recording element in an optical head including an optical element and an optical recording apparatus including the same as the illustrated embodiment. Not limited to. In addition, the same code | symbol and each corresponding part of each embodiment are attached | subjected the same code | symbol, and duplication description is abbreviate | omitted suitably.

FIG. 1 shows a schematic configuration example of an optical recording apparatus (for example, a hard disk apparatus) equipped with an optically assisted magnetic recording head. The optical recording apparatus 200 includes the following (1) to (6) in the housing 1.
(1) Recording disk (recording medium) 2
(2) Suspension 4 provided so as to be rotatable in the direction of arrow A (tracking direction) with support shaft 5 as a fulcrum.
(3) Tracking actuator 6 attached to the suspension 4
(4) Optically assisted magnetic recording head 3 attached to the tip of the suspension 4 (hereinafter referred to as the optical head 3)
(5) Motor for rotating the disk 2 in the direction of arrow B (not shown)
(6) Control unit 7 for controlling the tracking actuator 6, motor, recording, and the like.
Such an optical recording apparatus 200 is configured such that the optical head 3 can move relatively while flying over the disk 2.

  FIG. 2 shows a side view of the optical head 3 in which the suspension 4 is omitted as an example of the optical head 3. The optical head 3 is an optical head that uses light for information recording on the disk 2, and includes an optical element 21 and a slider 15. The optical element 21 includes an optical waveguide 16 that is a light transmitting portion, and is mounted on a slider 15 that is a base member having a flat upper surface that faces the bottom surface of the optical element 21. FIG. 3 is a perspective view of the optical element 21 constituting the optical head 3 as viewed from the bottom surface side (side facing the top surface of the slider 15). The optical element 21 and the slider 15 are coupled by an adhesive layer 13 provided in a gap formed by the convex portions 25, 26a, and 26b.

  The optical element 21 has a V-shaped groove 24 having a V-shaped cross-section and a light emitted from the optical fiber 11 on the slider 15. A deflection unit 20 that deflects in the direction is provided. The deflecting unit 20 includes an incident surface 23 on which light is incident and a deflecting surface 22 that deflects the incident light at a substantially right angle. An optical fiber 11 that guides light from, for example, a semiconductor laser, which is a light source (not shown), is fixed to the V groove 24.

  The light OP emitted from the optical fiber 11 reaches the convex portion 25 included in the optical element 21 through the incident surface 23 and the deflection surface 22 of the deflecting portion 20. The light OP represents the light beam as a representative light beam on the optical axis. The convex portion 25 functions as an optical waveguide, guides the light reaching the convex portion 25 and couples it to the optical waveguide 16 provided in the slider 15. The convex portion 25 will be further described later. The deflection surface 22 is an internal reflection surface using total reflection due to a difference in refractive index between the light transmission material forming the deflection unit 20, that is, the light transmission material forming the optical element 21 shown in FIG. Yes. By using total reflection, a good reflectance can be obtained without providing a metal film or the like for reflection.

  The slider 15 includes an optical waveguide 16, a magnetic recording unit 17, and a magnetic reproducing unit 18. The optical waveguide 16 emits light guided from the convex portion 25 on the upper end surface toward the disk 2 from the lower end surface, and the magnetic recording unit 17 writes magnetic information to the recording portion of the disk 2. The magnetic reproducing unit 18 has a function of reading magnetic information recorded on the disk 2. In FIG. 2, the magnetic reproducing section 18, the optical waveguide 16, and the magnetic recording section 17 are arranged in this order from the entry side to the withdrawal side (→ direction in the figure) of the recording area of the disk 2. Not exclusively. Since the magnetic recording unit 17 only needs to be positioned immediately after the exit side of the optical waveguide 16, for example, the optical waveguide 16, the magnetic recording unit 17, and the magnetic reproducing unit 18 may be arranged in this order. A light emitting surface of the optical waveguide 16 is provided with a minute metal structure (also referred to as a plasmon probe, not shown) that generates near-field light.

  The convex portions 25, 26a, and 26b provided on the bottom surface of the optical element 21 shown in FIG. The convex portions 25, 26 a, and 26 b are formed of a material described later that transmits the same light as that of the deflecting portion 20 as a part of the optical element 21.

  The light emitted from the optical fiber 11 enters from the incident surface 23 of the deflecting unit 20, is deflected by the deflecting surface 22, passes through the convex portion 25, and is emitted from the optical element 21. The tip of the convex portion 25 through which light passes is flat and is in contact with the incident surface of the optical waveguide 16 of the slider 15. For this reason, the light emitted from the optical element 21 can travel to the optical waveguide 16 of the slider 15 without traveling through the adhesive layer 13. For this reason, there is no light loss caused by Fresnel reflection due to the difference in refractive index between the material of the optical element 21 and the material of the adhesive layer 13 and the difference in refractive index between the material of the adhesive layer 13 and the material of the optical waveguide 16. In addition, no light loss occurs when there are contaminants such as bubbles in the light transmitting portion of the adhesive layer 13. Therefore, the optical element 21 and the optical waveguide 16 of the slider 15 can be coupled efficiently.

  Further, by making the refractive index of the material of the adhesive layer 13 surrounding the convex portion 25 smaller than the refractive index of the material of the optical element 21, the convex portion 25 functions as an optical waveguide for the transmitted light. be able to. Therefore, the light incident on the convex portion 25 is efficiently guided to the optical waveguide 16 in contact with the convex portion 25 while being confined in the convex portion 25. Further, the convex portion 25 functions as an optical waveguide, so that it is possible to improve the tolerance of the angle deviation and the axis deviation of incident light. In order for the convex portion 25 to function as an optical waveguide, any material having a refractive index smaller than the refractive index of the material forming the convex portion 25 may be used, and is not limited to the adhesive layer 13. A layer may be provided.

  The convex portions 26 a and 26 b through which light does not pass function as spacers, and are provided on the bottom surface of the optical element 21 so that the tip of the convex portion 25 and the top surface of the slider 15 are in contact with each other. By providing the convex portions 26 a and 26 b together with the convex portion 25, the light emitted from the convex portion 25 of the optical element 21 can be incident on the upper surface of the slider 15 so as to be perpendicular to the incident surface of the optical waveguide 16 of the slider 15. The optical element 21 can be provided easily and stably. The optical element 21 is stably fixed to the upper surface of the slider 15 by providing the adhesive layer 13 in the gap formed by the convex portions 25, 26a, and 26b between the upper surface of the slider 15 and the bottom surface of the optical element 21. Can do. Light loss caused by the light emitted from the optical element 21 entering the optical waveguide 16 at an angle is suppressed, and the light emitted from the optical element 21 is efficiently guided to the optical waveguide 16 of the slider 15 to improve the optical coupling efficiency. It can be.

  Further, since the convex portions 25, 26a, and 26b are fixed in contact with the upper surface of the slider 15, the distance between the optical element and the slider shown in the conventional optical head 300 in FIG. Thus, the positional deviation due to the thermal stress of the optical axis of the light incident on the optical waveguide is reduced, the optical loss caused by the positional deviation is suppressed, and the optical coupling efficiency can be improved.

  Since the convex portion 25 through which light passes is formed of a light transmitting material integrally with the optical element 21, the height of the convex portion 25 on the optical path until the light once incident on the optical element 21 exits from the convex portion 25. In the range of the optical path length difference due to the difference (about 0.5 μm to 0.3 mm), a substantially constant light transmission efficiency can be obtained. For this reason, with an increase in the distance between the bottom surface of the optical element and the top surface of the slider, there is almost no increase in light loss even if the convex portion 25 is made higher (longer). Therefore, the thickness of the adhesive layer between the bottom surface of the optical element and the top surface of the slider can be set according to the required coupling force between the optical element and the slider without concern about light loss. It can be determined appropriately depending on the height (length). An example in which the thickness of the adhesive layer that bonds the optical element and the slider is determined in accordance with the required bonding force is shown in FIG. 6 and will be described below.

  Taking the conventional optical head 300 shown in FIG. 9 as an example, the portion where the V-groove 24 for holding the optical fiber 11 is present may not sufficiently spread the adhesive, resulting in a decrease in adhesive force and peeling. . Further, the thermal stress in the portion with the V groove 24 is larger than the thermal stress in the portion without the V groove 24 due to the relationship between the bonding area and the thermal stress, and peeling may occur due to this thermal stress.

  With respect to the optical head 300, the optical head 3a shown in FIG. 6 has a height higher than the height of the convex portion 55 so that the adhesive can sufficiently spread over the portion of the V-groove 24 where the adhesive force decreases and thermal stress can be relieved. In this example, the height of the protrusions 56a and 56b is increased to thicken the adhesive layer 53 on the V-groove 24 side. The light emitted from the optical element 51 passes through the inside of the convex portion 55 and is incident on the optical waveguide 16 of the slider 15 without being inclined, so that it is efficiently transmitted with almost no optical loss, and the optical element 51. And the slider 15 can be bonded and fixed satisfactorily without peeling off.

  The shape of the convex portion that guides light is preferably a circular shape having symmetry with respect to the optical axis, as in the convex portion 25 shown in FIG. 3, but is not limited thereto. Further, the shape of the convex portion for guiding the light is a circular shape toward the traveling direction of the light in order to further improve the resistance against the axial deviation and angular deviation of the incident light, as shown by the convex portion 35 in FIG. In this case, it is preferable to use a truncated cone shape having a tapered portion with a small diameter. The optical element 31 shown in FIG. 4A shows an example including a frustoconical convex portion 35 in which the diameter of the circle decreases from the optical element 31 side toward the slider 15. FIG. 4B is a diagram showing a partial cross section taken along the line X-X ′ in FIG. By providing the convex portion 35 with the tapered portion, it is possible to further improve the function of the optical waveguide that guides the light OP1 and the light OP2 that are incident on the convex portion 35 with an axial deviation or angular deviation. it can.

  The optical element 41 of FIG. 5 shows an example in which the convex portion 45 that transmits light has a square frustum shape including a tapered portion including the convex portions 46a and 46b. Moreover, the convex part which does not inject | emits light is good also as a hemispherical convex shape which is easy to prescribe | regulate height instead of the shape where the front-end | tip shown to convex part 26a, 26b of FIG. 3 is flat (refer FIG. 8). The number of convex portions provided on the bottom surface of the optical element so as to be in contact with the top surface of the slider is preferably two or more including the convex portion transmitting light so that the optical element can be stably provided on the top surface of the slider. .

  Next, an example in which an optical fiber provided in a V-groove instead of the convex portions 26a and 26b provided on the bottom surface of the optical element will be described with reference to FIG.

  The optical element 61 in FIG. 7A shows an example provided with two convex portions 65a and 65b from which light is emitted. FIG. 7B shows a cross section at a position indicated by YY ′ in FIG. 7A in a state where the optical element 61 shown in FIG. 7A is mounted on the slider 15 to constitute the optical head 3b. Show.

  The optical element 61 is provided with two rows of V grooves 24 a and 24 b corresponding to the convex portions 65 a and 65 b, and the optical fibers 11 a and 11 b are fixed to the respective V grooves 24 a and 24 b with an adhesive 84. Since the depths of the V grooves 24 a and 24 b are reduced, a part of the outer periphery of the optical fibers 11 a and 11 b fixed to the V grooves 24 a and 24 b protrudes from the bottom surface of the optical element 61. The optical element 61 to which the optical fibers 11 a and 11 b are fixed is fixed to the slider 15 by the adhesive layer 83. The optical fibers 11a and 11b protrude from the bottom surface of the optical element 61 to the same height as the convex portions 65a and 65b and function as convex portions, and the thickness of the adhesive layer 83 is determined by this height.

  Since the optical fibers 11a and 11b are cylindrical, the portion in contact with the slider 15 is linear, and the tip of the optical fiber 11a and 11b can be pushed out more easily than when the tip is flat. The outer periphery of the shape and the slider 15 are more likely to be in close contact. Since the optical fibers 11a and 11b are in close contact with the slider 15 and mechanically contact with each other, the positional deviation due to the thermal stress between the optical fibers 11a and 11b and the slider 15 is reduced, and the deterioration of the optical characteristics due to the positional deviation is suppressed. Can do.

  The optical element 71 in FIG. 7C shows an example of a configuration in which light emitted from the two optical fibers 11c and 11d is collected at one point and emitted from the convex portion 75 to increase the light power. Similarly to FIG. 7A, the depths of the V grooves 24 c and 24 d are reduced, and the optical fibers 11 c and 11 d are fixed to the slider with a part of the outer circumference protruding from the bottom surface of the optical element 71.

  In the optical element 81 of FIG. 7D, the convex portion 85 and the optical fiber 11e that guides light are arranged on one line, and the shallow V grooves 24f and 24g having the same depth as the V groove 24e are formed into the V groove 24e. The optical fibers 11f and 11g are provided in these V grooves 24f and 24g. By providing the V grooves 24f and 24g and providing the optical fibers 11f and 11g thereto, the optical element 81 is stably fixed on the upper surface of the slider so as not to be inclined. The optical fibers 11f and 11g may be either one because they are in contact with the slider 15 by a line, or may be cylindrical members of the same shape that do not function as an optical fiber.

  FIG. 8A shows a side view of an optical head 3c including an optical element 91 and a slider 15 that are not provided with a V-groove to which an optical fiber is fixed. A magnetic recording unit, a magnetic reproducing unit, and a minute metal structure that generates near-field light are omitted. A focused light OP from a condensing optical system (not shown) enters the optical element 91, is deflected by the deflecting surface 22, and exits from the convex portion 95 toward the optical waveguide 16 included in the slider 15. The flat tip portion of the convex portion 95 is in contact with the upper surface of the optical waveguide 16.

  FIG. 8B shows a perspective view of an optical element 91 including two convex portions 96a and 96b in addition to the convex portion 95 that transmits light. The convex portions 96a and 96b have a hemispherical shape, and are in contact with the upper surface of the slider 15 at points. FIG. 8C shows a perspective view of an optical element 91 provided with one convex portion 96c in addition to the convex portion 95 that transmits light. The convex portion 96c has a hemispherical columnar cross-sectional shape and is in contact with the upper surface of the slider 15 with a line.

  An adhesive layer 93 is present in the gap between the optical element 91 and the slider 15. Since the refractive index of the material of the adhesive layer 93 is smaller than the refractive index of the material of the optical element 91, the convex portion 95 functions as an optical waveguide, and increases the allowable range for the angular deviation and axial deviation of the light OP. is doing. Further, by appropriately determining the heights of the convex portions 95, 96a, and 96b, it is possible to obtain sufficient adhesive strength as a desired thickness that can relieve stress concentration on the adhesive layer 93.

  As in the optical recording apparatus 200 shown in FIG. 1, when a large number of disks 2 as recording media are stacked to increase the capacity, it is preferable that the optical element fixed on the upper part of the slider is thin. For example, a femto slider used in a magnetic recording apparatus has a thickness of 0.23 mm, and the optical element is desired to be thinner.

  Assuming that the light spot size in a single mode fiber in the optical communication wavelength band (wavelength 1.3 μm to 1.5 μm band) is, for example, about 9 μm to 10 μm, the portion through which light passes is to keep the optical loss sufficiently small. It is considered necessary to secure an optical path width of about 5 times the spot size (for example, about 50 μm). Accordingly, in FIG. 8, the thickness and width of the optical element 91 are required to be about 50 to 100 μm, and the upper portion of the optical element 91 through which light does not pass is flat for thinning, and the convex portions 95 and 96a. , 96b, 96c are preferably about 0.5 to 50 μm in height.

  The material of the optical elements 21, 31, 41, etc. described so far may be silicon or glass, but is preferably made of a thermoplastic resin formed by an injection molding method or a press molding method. When a thermoplastic resin is used as a material, the shape of the V-groove and the convex portion constituting the optical element and the degree of freedom of arrangement thereof are high, and the manufacturing can be facilitated. Examples of the thermoplastic resin include polycarbonate and acrylic resin. Polycarbonate has a refractive index of 1.58 for visible light, for example, and acrylic resin has a refractive index of 1.49 for visible light. When manufacturing an optical element by mold molding using thermoplastic resin, if the convex part on the bottom surface of the optical element is made into a cone shape, the cone shape has a tapered part, so it is compared with a prismatic or cylindrical convex part Therefore, it is preferable because the mold can be easily removed.

  Examples of adhesives used for optical components include epoxy-based and acrylate-based refractive indexes in the range of, for example, a refractive index of 1.4 to 1.6. For example, as can be seen from the fact that the optical waveguide is configured with a refractive index difference of about 0.3% between the waveguide portion (core) and the surrounding (cladding) of a quartz single-mode optical fiber having a wavelength band of 1.3 μm to 1.5 μm. In addition, it is sufficient for the refractive index of the material of the adhesive layer to be about 0.3% lower than the refractive index of the material of the optical element in order to configure the optical waveguide with convex portions that transmit light. When the optical element is bonded and fixed to the slider, a convex portion that transmits light is used as an optical waveguide by appropriately selecting and using an adhesive made of a material having a refractive index smaller than the refractive index of the material of the optical element as described above. It can be easily functioned.

  The optical head described so far is an optically assisted magnetic recording head that uses light for information recording on the disk 2, but is an optical head that uses light for information recording on a recording medium. For example, an optical recording head that does not have the recording unit 17 and performs recording such as near-field optical recording and phase change recording can be provided.

It is a figure which shows the example of schematic structure of the optical recording device carrying an optically assisted magnetic recording head. The side view of an example of an optical head is shown. The perspective view which looked at the optical element which comprises an optical head from the bottom face side is shown. FIG. 4A shows an example of a truncated cone-shaped convex portion in which the diameter of the circle decreases from the optical element side toward the slider. FIG. 4B is a diagram illustrating a state of light incident on the frustoconical convex portion with a cross-sectional view in the vicinity and an axial and angular deviation. An example of a quadrangular frustum-shaped convex portion in which the square size decreases from the optical element side toward the slider is shown. It is a figure which shows the example of the optical head which adjusted the height of the convex part. It is a figure which shows another aspect of a convex part. It is a figure which shows the example of an optical head. It is a figure which shows an example of the conventional optical head.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Housing | casing 2 Disk 3, 3a, 3b, 3c, 300 Optical head 4 Suspension 11, 11a-11g Optical fiber (linear light guide)
13, 53, 83, 93, 103 Adhesive layer 15 Slider 16 Optical waveguide 17 Magnetic recording unit 18 Magnetic reproducing unit 21, 31, 41, 51, 61, 71, 81, 91, 101 Optical element 20 Deflection unit 22 Deflection surface 23 Incident surface 25, 26a, 26b, 35, 45, 46a, 46b, 55, 56a, 56b, 65a, 65b, 75, 85, 95, 96a, 96b, 96c Convex part 24, 24a-24g V groove 27 Bottom surface 200 Optical recording device OP, OP1, OP2

Claims (8)

An optical element that is mounted on a base member having a light transmission part and guides light from a light source to the light transmission part,
An optical element, wherein a convex portion that is in contact with the base member and transmits light from the light source is provided on a surface facing the base member, and a tip of the convex portion is flat. 2. The optical element according to claim 1, further comprising a convex portion whose tip is in contact with two or more base members including a convex portion having a flat tip. The optical element according to claim 1, wherein the material of the optical element is a thermoplastic resin. The optical element according to claim 1, further comprising a deflecting unit that deflects light from the light source toward the light transmitting unit. The optical element according to claim 4, further comprising a V-groove in which a linear light guide that guides the light to the deflecting unit is disposed. A base member having a light transmission part;
An optical head comprising: the optical element according to claim 1. The optical head according to claim 6, wherein an adhesive layer made of a material having a refractive index smaller than that of the material of the optical element is provided in a gap between the base member and the optical element. An optical recording apparatus comprising the optical head according to claim 6.

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