JP2007079318A - Optical element and its marking method, and assembling method for optical unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical element which can be assembled with high precision while minimizing damage to a part having an optical function, and facilitates information management of a history etc. <P>SOLUTION: A flange part 112 has an information mark M113 embedded in a portion of a ring. The mark M113 is easily observed not only along the optical axis of an objective body 101, but also obliquely to the optical axis. The information mark M113 is formed in a rectangular area having a two-dimensional extent. The information mark M113 includes characters, symbols, figures, patterns, etc., and can be, for example, a linear bar code, a two-dimensional bar code, etc., which are coded. The information mark M113 is a set of dotted modified areas or dotted crack areas formed in the flange part 112 to a specified depth by using a laser. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical element incorporated in a photographing lens or the like, a marking method for such an optical element, and a method for assembling an optical unit.

  Conventionally, a large number of optical elements (lens photographing and optical pickup lenses) for incorporation into various devices are packaged in a dedicated packaging material. In addition, providing the kind and lot number for each lens actually increases the cost, so it has not been realized despite the demand.

  However, recently, the final product has been diversified, and the variety has increased. That is, it is becoming a variety and small quantity production, and it is necessary to manage a huge variety of products.

  Further, in the photographic optical system, high-pixel digital still cameras have become mainstream, and accordingly, photographic optical elements are required to have high precision and high performance. Similarly, in the field of optical pickups, as the capacity is increased, the NA or wavelength is shortened, so that the required optical performance of each element constituting the optical pickup is improved by orders of magnitude. Further, the accuracy required for assembling / adjusting a photographic optical system using these elements and an optical pickup optical system is increasing.

  Under such circumstances, the problem that management of the optical element is very complicated has become remarkable. For example, (1) since there are a wide variety of optical elements, confusion easily occurs when configuring one optical system. (2) When there is some trouble with an optical element, when it is desired to investigate the history and the relationship thereof, the optical element itself has no information, so it is difficult to investigate the history.

  There are also the following problems. (3) When an optical system is assembled by assembling optical elements, an index for adjustment is required to achieve high assembly accuracy, but it is difficult to apply it at the manufacturing stage of the optical element. May also affect the performance of the optical element.

  On the other hand, conventionally, a technique called an internal marking (also called laser marking) method using a laser beam is known.

  For example, as a first marking method, there is a technique in which a transparent spectacle frame part (plastic) is irradiated with laser light to cause “burnt” inside to form a pattern (see Patent Document 1).

  As a second marking method, there is a technique for condensing a laser beam on a marking object such as a spectacle lens made of PMMA or other material and marking the inside without damaging the surface (see Patent Document 2). .

  As a third marking method, there is a technique in which, when internal marking is performed mainly on a thin glass material, laser irradiation is performed at a level that gives a change in optical properties, not crack generation (see Patent Document 3). .

As a fourth marking method, there is a technique in which a specific component is contained in a transparent resin, and a low-power active energy ray is irradiated to cause color development by a chemical reaction or to cause deformation due to a physical change (patent) Reference 4).
JP-A-2-242220 JP-A-3-124486 JP-A-11-267861 JP 2003-321616 A

  However, since the first and second marking methods damage the lens body, the information to be recorded cannot be increased.

  The third marking method is intended to write marks on a glass material, and the glass material itself does not have an optical function.

  The fourth marking method is intended to write a mark on the resin composition, and the resin composition itself does not have an optical function.

  Therefore, the present invention is an optical element having an optical surface, and enables high-precision assembly of the optical element and facilitates information management such as history while minimizing damage to a portion having an optical function. An object is to provide an optical element.

  It is another object of the present invention to provide a marking method for an optical element as described above and an assembling method for an optical unit incorporating the optical element as described above.

  In order to solve the above problems, a first optical element according to the present invention includes (a) an optical surface portion on which an optical surface is formed, and (b) a non-optical surface portion on which a non-optical surface is formed. And (c) a mark formed on or near the optical axis of the optical surface portion by laser marking and visually identifiable from the outside. Here, the “optical surface portion” is a portion that optically functions as an optical element, and means a portion through which light passing through an optical surface including a lens surface, a flat surface, a diffractive surface, a step surface, a diffusing surface, etc. To do. In addition, the “non-optical surface portion” is a portion that does not optically function as an optical element, and means a portion through which light passing through a non-optical surface that does not correspond to the optical surface passes.

  According to the above optical element, since the mark visually identifiable from the outside is formed on or near the optical axis of the optical surface portion by laser marking, alignment between the optical element and the holder, other optical elements, etc. Is simple and reliable, and the optical element can be assembled with high accuracy. In addition, since the formation of the mark is limited to the optical axis or the vicinity thereof, it is possible to minimize the loss of the optical function of the optical element.

  A second optical element according to the present invention includes (a) an optical surface portion on which an optical surface is formed, and (b) a non-optical surface portion on which a non-optical surface is formed, and (c) laser marking. Are formed on the non-optical surface portion and are visually identifiable from the outside.

  According to the optical element, since the mark visually identifiable from the outside is formed on the non-optical surface portion by laser marking, the optical function of the optical element is not impaired at all. Moreover, the non-optical surface portion is suitable for recording optical information in various states, and by recording with laser light, the degree of freedom of the recorded content can be increased, and the recorded content can be held securely. Can do.

  In a specific aspect of the present invention, the optical element includes data information in which a mark is represented by a formation pattern. In this case, encoded data information can be recorded as a mark, and the optical element can have a function as a data recording medium.

  In another aspect of the present invention, the mark is used as position information specified by the formation position. In this case, position information serving as an alignment index or the like can be recorded as a mark, and the optical element itself can have a function of specifying its orientation and orientation.

  In still another aspect of the present invention, the optical surface portion and the non-optical surface portion are formed of any one material of plastic, a composite material in which fine particles are mixed in plastic, and glass. In this case, surface processing and internal processing with laser light can be easily realized, and a transparent optical material is relatively easy to obtain.

  In yet another aspect of the invention, the mark modifies the optical properties of the material at that portion. In this case, damage to the optical material is reduced.

  In yet another aspect of the present invention, the mark causes the material to crack at that portion. In this case, the mark can be processed and formed efficiently.

  In yet another aspect of the present invention, the optical surface portion is used as an objective lens for an optical pickup. In this case, the optical element can be assembled to the optical pickup device with high accuracy while suppressing the optical function of the optical element from being impaired. Alternatively, an optical pickup device can be manufactured using an optical element in which optical information is freely recorded in various states.

  In yet another aspect of the present invention, the optical surface portion is used as a photographing lens. In this case, the optical element can be assembled to the photographing apparatus with high accuracy while suppressing the optical function of the optical element from being impaired. Alternatively, an imaging device can be manufactured using an optical element that freely records optical information in various states. can do.

  In still another aspect of the present invention, the mark has a three-dimensional shape or a planar shape, and can be read by observing from a predetermined direction. In this case, the mark can have a function as a data recording medium having a high recording density.

  An optical element marking method according to the present invention is an optical element marking method comprising an optical surface portion on which an optical surface is formed and a non-optical surface portion on which a non-optical surface is formed. By irradiating laser light onto or near the optical axis of the surface portion and / or the non-optical surface portion, a mark visually identifiable from the outside is formed.

  According to the marking method, a mark visually identifiable from the outside is formed on or near the optical axis of the optical surface portion by laser marking, or is formed on the non-optical surface portion by laser marking. Therefore, the optical element can be incorporated into the apparatus with high accuracy, and an optical element in which optical information is freely recorded in various states can be provided.

  In a specific aspect of the present invention, in the marking method, the mark is at least one of a character, a symbol, a pattern, and a barcode.

  In a specific aspect of the present invention, the wavelength of the laser light is included in the green wavelength range. In this case, the energy of the laser beam is relatively low and the optical element is hardly damaged, and the presence of the laser beam and the information recording process can be visually confirmed.

  In a specific aspect of the present invention, the mark is formed by irradiating the target position with laser light in a state where the non-optical surface portion is supported by a predetermined support means. In this case, the incident position and processing point of the laser beam are ensured, and high-precision and high-density writing is possible.

  In a specific aspect of the present invention, the optical element is a resin molded product, and the mark is formed after the optical element molding process and before the gate cut process, with the runner portion held. In this case, the mark can be written as a series of operations subsequent to the molding of the optical element.

  An optical unit assembly method according to the present invention is an optical unit assembly method in which a plurality of optical elements are combined, and is formed by irradiating at least two of the plurality of optical elements with laser light. Each with a marked mark. Then, shift adjustment and / or tilt adjustment of at least two optical elements is performed using the mark.

  According to the above assembling method, alignment such as optical axis shift and inclination between at least two optical elements can be performed with a mark visually identifiable from the outside, and high accuracy of the optical element is achieved by simple and reliable alignment. Can be assembled.

[First Embodiment]
Hereinafter, an objective lens unit according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1A is a side sectional view for explaining the objective lens unit of the first embodiment, and FIG. 1B is a side view of the objective lens body constituting the objective lens unit. 1C is a plan view of the objective lens body shown in FIG. 1B, and FIG. 1D is a plan view of the diffractive lens shown in FIG.

  The objective lens unit 50 is an optical unit that is compatible with two types of optical disks (for example, DVD and BD) having different standards (recording density and the like), and can record / reproduce information on these optical disks. It is configured to be possible. Further, the objective lens unit 50 collects laser light (use light) from a light source (not shown) to form a focused spot on an optical disk (not shown), and forms diffracted light. A diffractive lens 2 as a phase control element, and a cylindrical lens frame 3 as a support member for integrally fixing the objective lens body 1 and the diffractive lens 2.

  The objective lens body 1 is an aspherical meniscus lens in which the first surface 1a on the diffractive lens 2 side protrudes greatly and the second surface 1b on the optical disk side (right side of the drawing) is formed relatively flat. The diffracted light or non-diffracted light corresponding to a pair of different wavelengths is condensed at a predetermined location on each optical disk. The objective lens body 1 includes an optical surface portion 11 including first and second surfaces 1a and 1b which are optical surfaces, and an annular flange portion 12 which is a non-optical surface portion including a non-optical surface. The flange portion 12 is for supporting the optical surface portion 11 from the periphery.

  The objective lens body 1 can be formed from various glass materials and resin materials that can be normally used for optical applications such as lenses. When the objective lens body 1 is formed of a resin material, it is particularly preferable to use a resin containing a polymer having an alicyclic structure, and among them, it is more preferable to use a cyclic olefin resin.

  Further, a composite material such as an athermal resin can be used as the material of the objective lens body 1 as described above. The athermal resin is a material in which particles of, for example, 30 nm or less are dispersed in a resin as a base material. The athermal resin has a feature that the refractive index change with respect to the temperature change is small as compared with a resin for normal optical use.

  The diffractive lens 2 can form diffracted light by having a phase structure on the first surface 2 a opposite to the objective lens body 1. Note that the second surface 2b on the objective lens body 1 side is a flat surface in this case, and does not affect the image formation. The diffractive lens 2 includes an optical surface portion 21 including first and second surfaces 2a and 2b which are optical surfaces, and an annular flange portion 22 which is a non-optical surface portion including non-optical surfaces. The flange portion 22 is for supporting the optical surface portion 21 from the periphery.

  The diffractive lens 2 can also be formed from the same material as the objective lens body 1, that is, from various glass materials and resin materials. Further, an athermal resin can be used as the material of the diffractive lens 2. As described above, the athermal resin has a feature that the refractive index change with respect to the temperature change is small compared to the resin for the normal optical application as described above. This makes it possible to reduce the degradation of wavelength characteristics due to the phase structure, increase the degree of freedom in designing the diffractive lens 2, and increase the allowable range of manufacturing error and assembly accuracy. it can.

  As shown in FIG. 1D, the first surface 2a of the diffractive lens 2 is divided into a circular central area CA centered on the optical axis OA2 and a peripheral area PA around the central area CA. The central area CA has a phase structure, and the peripheral area PA is a flat surface. The central area CA has a diffractive property with respect to a laser beam with a wavelength of 655 nm for DVD, but does not have a diffractive property with respect to a laser beam with a wavelength of 405 nm for BD. That is, when a laser beam with a wavelength of 655 nm for DVD enters the central area CA, the laser light is diverged with a predetermined power due to a diffraction effect, and a laser beam with a wavelength of 405 nm for BD enters the central area CA and the peripheral area PA. In this case, the laser beam passes without any diffraction effect. In other words, in the case of this embodiment, the combination of the objective lens body 1 and the diffractive lens 2 makes it possible to form images compatible with both DVD and BD laser beams with a desired accuracy, and each laser beam is transmitted to each optical disc. It can be used as information reading light or information recording light.

  Positioning marks M11, M12, and M21 are formed by laser marking on the objective lens body 1 and the diffractive lens 2 as position information serving as a reference for positioning the center positions through which the optical axes OA1 and OA2 pass. ing. In the objective lens body 1 and the diffractive lens 2, positioning marks M13 and M23 are also formed by laser marking as position information serving as a reference for positioning the respective rotational positions.

  A pair of positioning marks M11 and M12 provided on the objective lens body 1 are arranged on the optical axis OA1. Thus, by providing the two positioning marks M11 and M12 on the optical axis OA1, the posture of the objective lens body 1 can be adjusted with respect to the inclination of the optical axis OA1, and the arrangement of the objective lens body 1 can be changed to the optical axis. Adjustments can be made with respect to the direction perpendicular to OA1. The positioning mark M21 provided on the diffractive lens 2 is disposed on the optical axis OA2. Thus, by providing the positioning mark M21 on the optical axis OA2, the arrangement of the diffractive lens 2 can be adjusted in the direction perpendicular to the optical axis OA2. Specifically, for example, when the positioning marks M11 and M12 are observed so as to match, the optical axis OA1 is oriented in the observation direction, and when the positioning marks M12 and M21 are observed to match, the objective lens body The center position through which the first optical axis OA1 passes and the center position through which the optical axis OA2 of the diffractive lens 2 passes are positioned with respect to each other, and alignment between the optical elements 1 and 2 becomes possible.

  The positioning mark M13 provided on the objective lens body 1 and the positioning mark M23 provided on the diffraction lens 2 are disposed on the flange portions 12 and 22 apart from the optical axes OA1 and OA2. Thus, by providing the positioning marks M13 and M23 away from the optical axes OA1 and OA2, the orientation of the objective lens body 1 and the diffraction lens 2 can be adjusted with respect to the direction perpendicular to the optical axis OA2.

  The lens frame 3 has a cylindrical outer shape and includes first and second fitting portions 34 and 35 having a step shape at both ends and an annular aperture 4. The first and second fitting portions 34 and 35 are for fixing the flange portions 12 and 22 of the objective lens body 1 and the diffractive lens 2 to the lens frame 3. The first fitting portion 34 is provided with play, and the objective lens body 1 can be finely moved in the direction perpendicular to the optical axis with respect to the lens frame 3 and can be rotated about the optical axis with respect to the lens frame 3. Is possible. The second fitting portion 35 is also provided with play so that the diffractive lens 2 can be finely moved in the direction perpendicular to the optical axis with respect to the lens frame 3 and around the optical axis with respect to the lens frame 3. It can be rotated.

  The diaphragm 10 disposed between the first fitting portion 34 and the second fitting portion 35 and disposed on the inner wall of the lens frame 3 performs unnecessary light cut and light amount adjustment when the objective lens unit 50 is used.

  Hereinafter, the manufacturing process of the objective lens unit 50 in the present embodiment will be described. First, the objective lens body 1 is attached to the lens frame 3. The flange portion 12 of the objective lens body 1 is brought into contact with the bottom reference surface of the first fitting portion 34. At this time, the objective lens body 1 can be rotated around the optical axis with respect to the lens frame 3 in the first fitting portion 34, and the direction of the objective lens body 1 is changed to the lens frame 3 by using the positioning mark M <b> 13. Point in the required direction. In this state, the UV adhesive is supplied to an appropriate portion of the edge of the flange portion 12 to cure the UV adhesive with ultraviolet rays. Thereby, the objective lens body 1 is fixed at a predetermined position.

  Next, the diffraction lens 2 is attached to the side facing the objective lens body 1 attached to the lens frame 3. The flange surface of the diffractive lens 2 is brought into contact with the bottom reference surface of the second fitting portion 35 to perform positioning with the objective lens body 1. That is, the diffractive lens 2 can be finely moved in the direction perpendicular to the optical axis with respect to the lens frame 3 within the second fitting portion 35, and the direction of the diffractive lens 2 with respect to the lens frame 3 is determined using the positioning mark M <b> 23. Turn in the direction you want. Specifically, for example, the positioning mark M23 of the diffraction lens 2 and the positioning mark M13 of the objective lens body 1 can be arranged so as to be aligned in a direction parallel to the optical axes OA1 and OA2. On the other hand, the diffractive lens 2 can be finely moved in the direction perpendicular to the optical axis with respect to the lens frame 3 in the second fitting portion 35, and the optical axis OA2 of the diffractive lens 2 is set to the objective lens body 1 using the positioning mark M21. To coincide with the optical axis OA1. Specifically, the positioning mark M21 is observed with a microscope or the like, and the diffraction lens 2 is moved (shift adjusted) so as to coincide with the positioning mark M12 of the objective lens body 1. Further, the positioning mark M21 is observed with a microscope or the like, and the diffraction lens 2 is moved (tilt adjusted) so as to match not only the positioning mark M12 of the objective lens body 1 but also the positioning mark M11. In this state, the UV adhesive is supplied to an appropriate portion of the edge of the flange portion 22 to cure the UV adhesive with ultraviolet rays. Thereby, the diffractive lens 2 is fixed at a predetermined position.

  Thus, the objective lens unit 50 is manufactured. As described above, the objective lens unit 50 has a three-part configuration in which the lens frame 3 is further used in addition to the objective lens body 1 and the diffractive lens 2, and alignment is not easy. By using the alignment method and assembly method as in the above embodiment, relative positioning of the objective lens body 1 and the diffractive lens 2 in the direction perpendicular to the optical axis can be performed with high accuracy in advance. The tilt state can also be adjusted. Since the positioning marks M11, M12, M13, M21, and M23 used in the above alignment are provided after the objective lens body 1 and the diffractive lens 2 are molded, the molding marks for these optical elements 1 and 2 are used. It is possible to completely avoid the influence on the molding conditions, which has been a problem when providing positioning marks in the molding stage by providing special irregularities. Further, since the positions of the positioning marks M11, M12, M13, M21, and M23 can be easily changed, the position and shape of the positioning marks can be quickly changed. Further, since the shape of the positioning marks M11, M12, M13, M21, and M23 can be freely changed with a certain degree of freedom as a visual index, the alignment work can be easily improved.

  In this description, with respect to the mounting order, the objective lens body 1 is first and the diffraction lens 2 is rear. This is for the convenience of design that it is easier to observe from the side of the diffractive lens 2 having a small refractive power during positioning. However, for example, when positioning is performed with the objective lens body 1 behind, the order of attachment may be changed. Further, as another fixing means, for example, both optical elements 1 and 2 can be fixed to the lens frame 3 by laser welding. In addition to the diffractive lens 2 side, there may be play in both the objective lens body 1 and the diffractive lens 2.

  FIG. 2 is a diagram for explaining a processing apparatus for forming the positioning marks M11, M12, M13, M21, and M23 on the objective lens unit 50 and the like shown in FIG.

  This processing apparatus includes a laser light source 81 that emits a collimated laser beam L, a scanning optical system 82 that changes the emission direction of the laser beam L two-dimensionally, and a laser beam L that has passed through the scanning optical system inside the workpiece W. And a stage 84 for supporting the workpiece W. Further, the processing apparatus operates the scanning optical system 82 at an appropriate timing to emit the laser light L in a necessary direction, and moves the condensing optical system 83 in the optical axis direction to move the workpiece W. The operation of the focus driving unit 86 for condensing light to a desired depth, the stage driving unit 87 for three-dimensionally displacing the stage 84, the scanning driving unit 85, the focus driving unit 86, and the stage driving unit 87 is controlled. A main controller 89. The workpiece W corresponds to the objective lens body 1 shown in FIG.

  In the above, the laser light source 81 emits the laser light L included in the green wavelength region. Specifically, a green laser having a wavelength in the vicinity of 550 nm was used. Since the laser beam L in the vicinity of 550 nm is visible light, the writing state can be visually confirmed. Further, the laser light L in the vicinity of 550 nm is relatively low in energy and hardly damages the objective lens body 1 or the like that is the workpiece W more than necessary. Furthermore, the laser light L in the vicinity of 550 nm can form a relatively small spot, and the processing efficiency is relatively high. Note that the level of processing by the laser light L is assumed to modify the optical properties of the target region of the material or to generate a crack in the target region of the material. When modifying the optical properties, it is conceivable to reduce the transmittance or increase or decrease the refractive index, Abbe number, temperature coefficient of refractive index, or the like. Further, when cracks are generated, a minute breakage occurs in the target area, but it is conceivable to adjust the size or the like. Adjustment of the processing level as described above is achieved by setting the energy of the laser light L emitted from the laser light source 81 and the convergence angle by the condensing optical system 83.

  The stage 84 supports the workpiece W on a flat upper surface 84a as a support means. At this time, the upper surface 84a is provided with a protruding limiting member 84b for limiting the movement of the workpiece W for alignment. Thereby, the movement of the workpiece W, that is, the objective lens main body 1 is restricted in the optical axis direction by the upper surface 84a, and the movement is restricted by being abutted in a certain direction perpendicular to the optical axis by the restriction member 84b. As a result, the workpiece W is stably and accurately positioned and held on the stage 84, the influence of disturbance is prevented, and the positioning marks M11, M12, M13, M21, and M23 are written by the laser beam L. Can be performed precisely as intended.

  The scanning drive unit 85 can scan the condensing position of the laser light L in cooperation with the scanning optical system 82, and the condensing position of the laser light L can be arbitrarily determined two-dimensionally along the upper surface 84 a of the stage 84. It can be moved to the position.

  The focus driving unit 86 can change the condensing position with respect to the traveling direction of the laser light L in cooperation with the condensing optical system 83, and the condensing position of the laser light L is set to be perpendicular to the upper surface 84 a of the stage 84. It can be moved freely.

  That is, the condensing position of the laser light L can be moved three-dimensionally to an arbitrary position by appropriately operating the scanning drive unit 85 and the focus drive unit 86 under the control of the main controller 89. That is, if the shape of the workpiece W is stored in the main controller 89 in advance, a modified region or a crack region can be formed on the surface of the workpiece W or at an arbitrary position inside. At this time, by adjusting the operation timing of the laser light source 81 under the control of the main controller 89, the region in which the optical properties are modified or cracks are generated is made to be a dot-like or a portion having a certain spread. Can do.

  The stage driving unit 87 can move, rotate, or tilt the workpiece W in any three-dimensional position in cooperation with the stage 84.

  By using the processing apparatus described above, positioning marks M11, M12, and M13 as shown in FIGS. 1A to 1C can be formed on the objective lens body 1, and FIGS. The positioning marks M21 and M23 as shown in FIG. In addition, the workpiece | work W which is the object which forms the positioning marks M11, M12, M13, M21, and M23 by the processing apparatus of FIG. Here, when the anti-reflection coating is applied to the molded optical element, the positioning marks M11, M12, M13, M21, and M23 can be written on the workpiece W at any stage before and after the coating. . Further, when the annealed optical element is subjected to the annealing treatment, the positioning marks M11, M12, M13, M21, and M23 can be written on the workpiece W at any stage before and after the annealing.

  FIG. 3 is a diagram for explaining a modification of the processing apparatus shown in FIG. In this case, the workpiece W is a semi-finished product immediately after being formed, and includes a sprue portion Wa, a runner portion Wb, a gate portion Wc, and a product portion Wd. The four product parts Wd correspond to the objective lens body 1 and are parts that should be finally separated from the gate part Wc. The workpiece W is held by a robot hand 184 instead of the stage 84 so that the runner portion Wb is pressed against the abutting member 187 constituting the supporting means together with the robot hand 184 with a constant force for precise positioning. It has become. Thus, by holding and guiding the runner portion Wb, the product portion Wd can be securely held, and particularly, a small lens, that is, the product portion Wd can be easily held, and the writing position accuracy of the laser beam L is improved. To do.

  FIG. 4 is a diagram schematically showing the configuration of an optical pickup device incorporating the objective lens unit 50 shown in FIG.

  In this optical pickup device, the laser light from each of the semiconductor lasers 61B and 61D is applied to the optical discs DB and DD which are optical information recording media using the objective lens unit 50, and the reflected light from each of the optical discs DB and DD is Through the common objective lens unit 50, the light is finally guided to the photodetectors 67B and 67D.

  Here, the first semiconductor laser 61B generates laser light for information reproduction (for example, for BD, wavelength 405 nm) of the first optical disc DB, and this laser light is condensed by the objective lens unit 50 and is equivalent to NA 0.85. Are formed on the information recording surface. The second semiconductor laser 61D generates laser light for reproducing information from the second optical disk DD (for example, for DVD, wavelength 655 nm), and then the laser light is condensed by the objective lens unit 50, and a spot corresponding to NA 0.65 is formed. It is formed on the information recording surface. The first photodetector 67B detects information recorded on the first optical disc DB as an optical signal (for example, for BD, wavelength 405 nm), and the second photodetector 67D is recorded on the second optical disc DD. Information is detected as an optical signal (for example, for DVD, wavelength 655 nm).

  First, when reproducing the first optical disc DB, laser light having a wavelength of, for example, 405 nm is emitted from the first semiconductor laser 61B, and the emitted light beam becomes a parallel light beam by the collimator 62B. This light beam passes through the polarization beam splitters 63B and 64D and the quarter-wave plate 69 and is then focused on the information recording surface MB of the first optical disc DB by the objective lens unit 50.

  The light beam modulated and reflected by the information bit on the information recording surface MB is again transmitted through the objective lens unit 50 and the like, and is incident on the polarization beam splitter 63B, where it is reflected and given astigmatism by the cylindrical lens 65B. Then, the light is incident on the first photodetector 67B, and a read signal of information recorded on the first optical disc DB is obtained using the output signal.

  Further, a change in the amount of light due to a change in the shape of the spot and a change in position on the first photodetector 67B is detected to perform focus detection and track detection. Based on this detection, a two-dimensional actuator 73 comprising an actuator portion 71 provided on the holder member 55 that holds the objective lens unit 50 and an actuator portion 72 provided on the fixing member 56 is used as a luminous flux from the first semiconductor laser 61B. The objective lens unit 50 is moved in the direction of the optical axis so as to form an image on the information recording surface MB of the first optical disc DB, and the object is formed so that the light flux from the first semiconductor laser 61B is imaged on a predetermined track. The lens unit 50 is moved in a direction perpendicular to the optical axis.

  Next, when reproducing the second optical disk DD, laser light having a wavelength of, for example, 655 nm is emitted from the second semiconductor laser 61D, and the emitted light beam is converted into a parallel light beam by the collimator 62D. This light beam passes through the polarization beam splitter 63D, is reflected by the polarization beam splitter 64D, and is collected by the objective lens unit 50 on the information recording surface MD of the second optical disc DD.

  The light beam modulated and reflected by the information bit on the information recording surface MD is transmitted again through the objective lens unit 50 and the like, reflected by the polarization beam splitter 64D and incident on the polarization beam splitter 63D, and reflected and reflected here by the cylindrical lens 65D. Astigmatism is given by the laser beam, the light is incident on the second photodetector 67D, and a read signal of information recorded on the second optical disk DD is obtained using the output signal.

  Further, as in the case of the first optical disc DB, a change in the amount of light due to a change in the shape and position of the spot on the second photodetector 67D is detected, and focus detection and track detection are performed, and the objective lens unit 50 is held. The objective lens unit 50 is moved for focusing and tracking by a two-dimensional actuator 73 provided accompanying the holder member 55 and the like.

  According to the above optical pickup device, the objective lens unit 50 assembled with high accuracy and good workability is incorporated, so that high-precision optical information recording and / or reproduction is possible, and as a result, cost reduction can be achieved.

  By the way, in the above description, the positioning marks M11, M12, and M21 are formed not inside these surfaces but inside the optical surface portions 11 and 21 of the optical elements 1 and 2 at a depth of 0.1 mm to several mm or more. However, the positioning marks M11, M12, and M21 may be formed on the surfaces of the optical surface portions 11 and 21, that is, the optical surfaces 1a, 1b, 2a, and 2b. In this case, the optical surface is roughened on and near the optical axis. On the other hand, in the flange portions 12 and 22 of the optical elements 1 and 2, the positioning marks M13 and M13 are formed inside 0.1 mm to several mm or more from the surface, but the positioning marks M11 and M13 are formed on the surface of the flange portion 12. M12 and M21 can also be formed. In this case, the non-optical surface that is the surface of the flange portion 12 is roughened.

[Second Embodiment]
Hereinafter, the objective lens unit of the second embodiment will be described. The objective lens unit of the second embodiment is a modification of the objective lens unit 50 of the first embodiment shown in FIG. 1, and parts not specifically described are the same as those of the first embodiment.

  FIG. 5A is a perspective view of the objective lens main body 101 constituting the objective lens unit of the second embodiment, and FIG. 5B is a partially enlarged view of the objective lens main body 101 shown in FIG. It is. This objective lens body 101 is incorporated in the objective lens unit 50 shown in FIG.

  The objective lens body 101 includes an optical surface portion 11 formed of an optical surface and a flange portion 112 formed of a non-optical surface. Unlike the objective lens body 1 shown in FIG. 1A, the flange portion 112 has an information mark M113 embedded in an annular part. The mark M113 can be observed not only from the direction of the optical axis of the objective lens body 101, but also from the direction inclined with respect to the direction of the optical axis. Note that the inclination direction of the information mark M113 is not limited to that illustrated in FIG.

  In the illustrated example, the information mark M113 is formed in a rectangular region having a planar spread. The information mark M113 includes data, characters, symbols, figures, patterns, etc. as data information. The characters, symbols, figures, patterns, etc. constituting the information marks M113 are coded one-dimensional barcodes, for example. It can be a two-dimensional barcode or the like. The information mark M113 is an aggregate of dot-shaped modified regions and dot-shaped crack regions formed at a predetermined depth inside the flange portion 112 using a laser, and each dot has a size of, for example, 2 to 50 μm. is there. Further, the information mark M113 is observed as a portion where the transmittance is reduced by about 30% due to a phenomenon such as scattering.

  The information mark M113 can be observed with the naked eye or a microscope while the objective lens body 101 is placed on the observation stage, and the recorded content can be automatically recognized by capturing the image and processing it. Can be. The information mark M113 can be observed, for example, from the direction of the optical axis when the objective lens body 101 is handled alone, but after the objective lens body 101 is incorporated into the objective lens unit 50, It is desirable to form it at a place where it can be observed from the outside.

  When writing characters as the information mark M113, the model number, type, lot number, cavity number, injection condition, date and time of manufacture, manufacturing factory, material, post-processing condition, manufacturing company name, patent number, URL (universal) resource locator) Any one or a combination of other index information can be recorded. In the above, the cavity number is a number unique to the mold when the objective lens main body 101 is molded, and there are cases where the optical characteristics of the objective lens main body 101 have relevance or correlation. The injection conditions are conditions including the temperature when the objective lens body 101 is injection-molded, the material supply speed, and the like. The post-processing conditions mean post-processing conditions including coating, annealing, and the like. Further, regarding the URL, various types of information regarding the objective lens body 101 can be acquired using the Internet. In addition, not only URL but various index information can be recorded, Here, index information means the character for associating a group of data with the objective lens main body 101. By recording various character information as described above, the performance, usage, history, etc. of the objective lens main body 101 can be grasped and managed. Can be increased.

  When a symbol, figure, pattern, or the like is written as the information mark M113, for example, a trademark for the objective lens body 101 can be written. When recording a barcode as the information mark M113, the model number, type, lot number, cavity number, injection condition, date and time of manufacture, manufacturing factory, material, post-processing condition, manufacturer name, patent number, Any one or a combination of URLs or the like can be included as information. If the bar code is related to a patent number, the decoding can result in a series of patent numbers associated with the objective lens body 101, for example. When the barcode is related to URL or other index information, data corresponding to the Internet site, memory address, etc. corresponding to the index information can be referred to. Such data is not limited to the model number, product type, lot number, cavity number, injection condition, manufacturing date, manufacturing factory, material, post-processing condition, manufacturing company name, patent number, etc. It can also be a program related to the handling of Such a program corresponds to an inspection program, an assembly program, and the like for the objective lens body 101.

  In addition, when writing a symbol, a figure, a pattern or the like as the information mark M113, a model number, a product type, a lot number, a cabinet number, an injection condition, a manufacturing date, a manufacturing factory, a material, a post-processing condition, a manufacturing company name, a patent number, an index It can also be a symbol obtained by symbolizing character information such as information.

  According to the optical element described above, that is, the objective lens main body 101, not only the objective lens main body 101 and thus the objective lens unit can be individually identified and confirmed, but also history management and lot management are possible. History management and lot management can also be used for feedback of defective products when the objective lens body 101 is incorporated into an optical pickup device to produce a product.

  In the above description, the information mark M113 is formed not on the surface of the flange portion 112 but inside, but the information mark M113 can be formed on the surface of the flange portion 112. In this case, the non-optical surface that is the surface of the flange portion 112 is roughened.

[Third Embodiment]
The objective lens unit according to the third embodiment will be described below. The objective lens unit of the third embodiment is a modification of the first embodiment.

  FIG. 6 is a partially enlarged view of the objective lens body constituting the objective lens unit of the third embodiment. In the case of the objective lens body 201, three types of information marks M213a, M213b, and M213c are formed in the flange portion 212.

  For example, the first information mark M213a has a pattern that spreads along a plane perpendicular to the optical axis of the objective lens body 201, and is easy to see from the optical axis direction of the objective lens body 201. The second information mark M213b has a pattern extending along a plane perpendicular to the perpendicular extending from the optical axis of the objective lens body 201, and is easily visible from the side surface side of the objective lens body 201. Such an information mark M213b is easy to see even when assembled in a unit that sandwiches the objective lens body 201 from both sides. The third information mark M213c has a pattern extending along a plane parallel to a perpendicular extending from the optical axis of the objective lens body 201.

  Note that the outlines of the information marks M213a, M213b, and M213c are not limited to the rectangular shape shown in the figure, and may have various shapes, and it is not necessary to provide the outline.

  Further, the information marks M213a, M213b, and M213c do not need to be provided as a group as illustrated, and can be provided individually, and a plurality of the same type of information marks M213a, M213b, and M213c can be provided.

[Fourth Embodiment]
The objective lens unit according to the fourth embodiment will be described below. The objective lens unit of the fourth embodiment is a modification of the first embodiment.

  FIG. 7 is a partially enlarged view of the objective lens body constituting the objective lens unit of the fourth embodiment. In the case of the objective lens body 301, a three-dimensional information mark M313 is formed in the flange portion 312.

[Fifth Embodiment]
FIG. 8 is a side sectional view for explaining the structure of an image pickup apparatus including the photographing optical system according to the fifth embodiment. The imaging device 590 is a cylindrical device, and includes an imaging optical system 591, an image sensor 596, a circuit board 597, and a housing 599, and the imaging optical system 591 is configured by the circuit board 597 and the housing 599. The image sensor 597 is sealed inside while facing the image sensor 597.

  The imaging optical system 591 is an optical unit as a photographing lens, and includes an infrared absorption filter 592, a light shielding plate 593, a first lens 594, and a second lens 595. The infrared absorption filter 592 is integrated with the light shielding plate 593 and is fixed by being fitted into one opening of the housing 599. In addition, the first lens 594 and the second lens 595 are fixed to each other using an adhesive or the like at the flange portions 594b and 595b. Both lenses 594 and 595 are fitted to fill the inside of the housing 599 and are fixed in the housing 599. At this time, the optical surface portion of the first lens 594, that is, the lens portion 594a, and the optical surface portion of the second lens 595, that is, the lens portion 595a, are aligned with each other.

  On the other hand, the image sensor 596 is a semiconductor integrated circuit including, for example, a CMOS type image sensor or the like, and is bonded to the upper surface of the circuit board 597. The upper surface 596 a of the image sensor 596 has an image pickup surface at the center, and the wiring 596 c extending from the image sensor 596 is connected to the wiring pattern on the circuit board 597. The lower end of the leg portion 595c of the second lens 595 is in contact with the peripheral portion of the upper surface 596a of the image sensor 596, so that the distance between the image sensor 596 and the lens portion 595a of the second lens 595 is appropriately maintained.

  In the imaging optical system 591 described above, the same positioning marks as the positioning marks M11, M12, and M21 shown in FIG. 1 are formed on the lens portion 594a of the first lens 594 and the lens portion 595a of the second lens 595. be able to. Further, on the flange portion 594b of the first lens 594 and the flange portion 595b of the second lens 595, a positioning mark similar to the positioning marks M13 and M23 shown in FIG. 1 and an information mark M113 exemplified in FIG. , M213a, M213b, M213c, and the like can be formed.

  Although the present invention has been described based on the above embodiments, the present invention is not limited to the above embodiments, and various modifications are possible. For example, in the above embodiment, the positioning marks M11, M12, M13, M21, M23, the information marks M113, M213a, M213b, M213c, etc. are formed on the objective lens, the diffractive lens, etc., but other types of optical elements, for example, Positioning marks and information marks can also be formed on various optical elements such as cylindrical lenses, coupling lenses, collimating lenses, fθ (F-theta) lenses, and prisms.

(A) is side sectional drawing of the objective lens unit of 1st Embodiment, (b) and (c) are the side view and top view of the 1st optical element which comprise an objective lens unit, ( d) is a plan view of a second optical element constituting the objective lens unit. It is a block diagram explaining the processing apparatus which forms a mark in the objective lens unit shown in FIG. It is a perspective view explaining the modification of the processing apparatus shown in FIG. It is a figure explaining the optical pick-up apparatus incorporating the objective-lens unit demonstrated in FIG. (A) is a perspective view of the 1st optical element which comprises the objective-lens unit of 2nd Embodiment, (b) is an expansion perspective view explaining a part of 1st optical element. It is an expansion perspective view explaining a part of 1st optical element which comprises the objective-lens unit of 3rd Embodiment. It is an expansion perspective view explaining a part of 1st optical element which comprises the objective-lens unit of 4th Embodiment. It is a side sectional view explaining the photographing optical system of a 5th embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Objective lens main body, 1a, 1b ... 2nd surface, 2 ... Diffraction lens, 2a ... 1st surface, 2b ... 2nd surface, 3 ... Mirror frame, 11 ... Optical surface part, 11, 21 ... Optical surface part, 12, 22 ... flange portion, 50 ... objective lens unit, 61B, 61D ... semiconductor laser, 67B, 67D ... photodetector, 73 ... two-dimensional actuator, 81 ... laser light source, 82 ... scanning optical system, 83 ... condensing optics System, 84 ... Stage, 89 ... Main controller, DB, DD ... Optical disk, L ... Laser light, M11, M12, M13, M21, M23 ... Positioning mark, M113, M213a, M213b, M213c ... Information mark, MB ... Information Recording surface, MD: Information recording surface

Claims (16)

An optical surface portion formed with an optical surface;
A non-optical surface portion formed with a non-optical surface,
A mark formed on or near the optical axis of the optical surface portion by laser marking, and visually identifiable from the outside;
An optical element comprising: An optical surface portion formed with an optical surface;
A non-optical surface portion formed by the non-optical surface,
A mark formed on the non-optical surface portion by laser marking and visually identifiable from the outside;
An optical element comprising:   The optical element according to claim 2, wherein the mark includes data information represented by a formation pattern.   The optical element according to claim 2, wherein the mark is used as position information specified by a formation position.   The optical surface portion and the non-optical surface portion are formed of any one of plastic, a composite material in which fine particles are mixed in plastic, and glass. The optical element described.   The optical element according to any one of claims 1 to 5, wherein the mark modifies the optical properties of the material at that portion.   The optical element according to claim 1, wherein the mark causes a crack in the material at that portion.   The optical element according to any one of claims 1 to 7, wherein the optical surface portion is used as an objective lens for an optical pickup.   The optical element according to any one of claims 1 to 7, wherein the optical surface portion is used as a lens for photographing.   The optical element according to any one of claims 1 to 9, wherein the mark has a three-dimensional shape or a planar shape, and can be read by observing the mark from a predetermined direction. An optical element marking method comprising an optical surface portion formed with an optical surface and a non-optical surface portion formed with a non-optical surface,
An optical element characterized by forming a mark visually identifiable from the outside by irradiating a laser beam on or near the optical axis of the optical surface portion and / or the non-optical surface portion. Marking method.   The optical element marking method according to claim 11, wherein the mark is at least one of a character, a symbol, a pattern, and a barcode.   The optical element marking method according to claim 11, wherein a wavelength of the laser light is included in a green wavelength region.   14. The method of marking an optical element according to claim 11, wherein the mark is formed by irradiating a target position with laser light in a state where the non-optical surface portion is supported by a predetermined support means.   The said optical element is a resin molded product, The formation of the said mark is after the shaping | molding process of the said optical element and before a gate cut process, and is performed in the state which hold | maintained the runner part. The marking method of the optical element as described in any one of 14. An assembly method of an optical unit combining a plurality of optical elements,
At least two of the plurality of optical elements each have a mark formed by irradiating with laser light,
A method of assembling an optical unit, wherein shift adjustment and / or tilt adjustment of the at least two optical elements is performed using the mark.

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