JP2008185832A - Optical element and method for assembling optical unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical element suitable for adjustment and verification of the tilt of an optical axis when assembling the optical unit, and to provide a method for assembling the optical unit. <P>SOLUTION: The optical element (optical lens 10) includes optical functional surfaces 12a and 14a for refracting or reflecting incident light, and a reference surface formed as a flat reflection mirror surface 18 on the more outside than the optical functional surface in order to show the direction of the optical axis P1. By such an arrangement, since the optical element includes the reference surface formed as the flat reflection mirror surface, the direction of the optical axis of the optical element is confirmed by measuring reflected light reflected from the reference surface. Accordingly, when assembling the optical unit (lens barrel 20), the optical element is assembled in the optical unit while measuring the tilt of the optical axis of the optical element in the optical unit. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical element and an optical unit assembling method, and more particularly to an optical element and an optical unit assembling method suitable for adjusting and verifying the inclination of the optical axis of the optical element.

  In general, when assembling an optical unit that is applied to a photographing device such as a camera or a TV camera, the resolution is obtained by observing the imaging state of the optical system with a microscope or the like in a state where a plurality of optical lenses are incorporated in the optical unit. Adjustments are made to improve the level. By this adjustment, a decrease in optical performance due to the inclination or decentering of the optical axis of the optical lens constituting the optical unit is suppressed.

  Conventionally, in this type of tilt adjustment and eccentricity adjustment, first, if necessary, some optical lenses other than the adjustment target are removed from the optical unit, and the holding member that holds the adjustment target optical lens is tightened. Relaxed. Then, the optical lens is tilted alone or together with the holding member, rotated around the optical axis, or moved in a plane perpendicular to the optical axis, so that the tilt and eccentricity are adjusted.

  Further, in Patent Document 1 below, a bent portion provided at the boundary between the optical function surface and the flange surface of the optical lens is photographed by the coaxial epi-illumination method and subjected to image processing. A method for verifying the center of the optical axis of an optical lens incorporated in an optical unit by measuring the arrangement of bent portions that appear is disclosed.

JP 2005-134672 A

  However, in the conventional assembly process, the optical lens to be adjusted is adjusted after verifying the image formation state of the optical system with all the optical lenses assembled in the optical unit. Disassembly work is required. The verification method disclosed in Patent Document 1 is an excellent method that can accurately verify the center of the optical axis of an optical lens incorporated in the optical unit. Therefore, the tilt of the optical axis cannot be fully verified. Furthermore, in the conventional assembly process, the inclination of the optical axis of the optical lens is adjusted by simply abutting the optical lens against a reference surface provided in the optical unit, so that sufficient assembly accuracy cannot be obtained.

  The present invention has been made in view of the above problems, and an object of the present invention is to assemble a new and improved optical element and optical unit suitable for adjusting and verifying the tilt of an optical axis when an optical unit is assembled. It is to provide a method.

  In order to solve the above problems, according to an aspect of the present invention, an optical functional surface for refracting or reflecting incident light and a reflecting mirror surface that is flat outside the optical functional surface to indicate the direction of the optical axis. And a reference surface formed as an optical element.

  According to this configuration, since the optical element includes the reference surface formed as a flat reflecting mirror surface, the direction of the optical axis of the optical element is confirmed by measuring the reflected light reflected from the reference surface. Therefore, when the optical unit is assembled, the optical element can be incorporated into the optical unit while measuring the inclination of the optical axis of the optical element in the optical unit.

  The optical element may be formed as an optical lens. According to this configuration, when the optical unit is assembled, the optical lens can be incorporated into the optical unit while measuring the inclination of the optical axis of the optical lens in the optical unit.

  The reference plane may be a plane orthogonal to the optical axis. According to this configuration, since the optical element includes the reference surface formed as a surface orthogonal to the optical axis, the projection light parallel to the optical axis of the optical element is projected, so that the reflection parallel to the optical axis of the optical element is performed. Light is measured.

  Further, a flange portion may be provided outside the optical function surface, and the reference surface may be formed on a surface constituting the flange portion. According to this configuration, since the optical element includes the reference surface formed on the surface constituting the flange portion, the projection light is reliably projected onto the reference surface and the optical axis of the optical element is reliably tilted. Measured.

  The reference plane may be formed with an arithmetic average roughness (Ra) of 20 nm or less. According to this configuration, since the optical element includes the reference surface with high reflection characteristics, the projection light is reliably reflected by the reference surface.

  The optical element may be made of glass. According to this configuration, an optical element made of glass suitable for adjusting and verifying the inclination of the optical axis is formed.

  The optical element may be made of plastic. According to this configuration, an optical element made of plastic that is suitable for adjustment and verification of the inclination of the optical axis is formed.

  Further, a substantially cylindrical surface that is coaxial with the optical axis and protrudes in the direction of the optical axis may be formed on the back side of the reference surface formed on the flange portion. According to this configuration, since the optical element includes the flange surface formed with the substantially cylindrical surface that is coaxial with the optical axis and protrudes in the direction of the optical axis, the direct or indirect connection between the substantially cylindrical surface and the mounting surface of the optical element. The optical element is assembled into the optical unit through simple contact.

  Further, according to another aspect of the present invention, a step of projecting projection light onto a reference surface formed on the optical element as a flat reflecting mirror surface to indicate the direction of the optical axis of the optical element, and reflected from the reference surface There is provided an assembling method of an optical unit characterized by including a step of measuring reflected light and a step of adjusting an inclination of an optical axis of an optical element in the optical unit.

  According to this method, since the projection light is projected onto the reference surface formed on the optical element as a flat reflecting mirror surface, the direction of the optical axis of the optical element is confirmed by measuring the reflected light reflected from the reference surface. The Therefore, when the optical unit is assembled, the optical element can be incorporated into the optical unit while measuring the inclination of the optical axis of the optical element in the optical unit.

  Moreover, you may make it further include the process of verifying the inclination of the optical axis of an optical element in the said optical unit. According to this method, the inclination of the optical axis of the optical element is verified in a state where it is incorporated in the optical unit.

  As described above, according to the present invention, it is possible to provide an optical element and an optical unit assembly method suitable for adjusting and verifying the inclination of the optical axis when the optical unit is assembled.

  Below, the case where this invention is applied to the optical lens which is an example of an optical element is demonstrated in detail. However, the present invention is not limited to an optical lens, and can also be applied to optical elements such as a mirror such as a concave mirror and a convex mirror, a solid immersion lens, a solid immersion mirror, and a prism.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the present specification and drawings, components having substantially the same function are denoted by the same reference numerals, and redundant description is omitted.

  First, an optical lens according to an embodiment of the present invention will be described. FIG. 1 is an explanatory view showing an optical lens according to an embodiment of the present invention. 1A shows a sectional view of the optical lens, and FIG. 1B shows a plan view when the optical lens shown in FIG. 1A is viewed from the right side. Yes.

  As shown in FIG. 1, the optical lens 10 includes first and second optical function surfaces 12 a and 14 a made of, for example, convex aspheric surfaces, and first edges that respectively constitute outer edges of the optical function surfaces 12 a and 14 a. And second flange surfaces 12b, 14b. The first flange surface 12b is provided with, for example, a protruding portion 16 that protrudes in the direction of the optical axis P1 of the optical lens 10 and has a protruding surface 16a that is substantially orthogonal to the optical axis P1 and a cylindrical surface 16b that is substantially coaxial with the optical axis P1. It is done. When the optical lens 10 is attached to the lens frame 24 (see FIG. 5C), the protrusion 16 improves the positioning accuracy at the time of attachment by the protrusion surface 16a and the cylindrical surface 16b and increases the contact area to increase the optical accuracy. The adhesive strength between the lens 10 and the lens frame 24 is improved. On the other hand, the second flange surface 14b is formed so as to be substantially orthogonal to the optical axis P1 of the optical lens 10 in this case.

  Here, the optical functional surface of the optical lens 10 is the effective diameter of the optical lens (the diameter of the cross-section perpendicular to the optical axis of the parallel light bundle that should pass through the optical lens from the infinity point on the optical axis). The range to the outside including the range is shown, and it is difficult to process according to the design shape for realizing the function as an optical lens in molding only for the effective diameter range, so the effective diameter range In addition, it means a range molded with a predetermined design shape for realizing the function as an optical lens.

  This type of optical lens 10 is molded by an injection molding method, a press molding method, or the like. The injection molding method is a molding method in which an optical lens is molded from a molding material through each process of mold clamping, injection, holding pressure, cooling, plasticizing, and mold opening. In the injection molding method, for example, the mold is clamped at a pressure equal to or higher than the injection pressure, the molding material is injected into the molding mold, the pressure applied to the molding material is maintained, and the molding material is cooled and cured to obtain a desired value. An optical lens is molded. The press molding method is a molding method in which an optical lens is molded from a molding material using a pair of molding dies provided with a transfer surface including an optical function transfer surface, and a body die into which the molding dies are inserted. In the press molding method, for example, a molding material is placed on one molding die, and the molding material is heated and softened, pressed with a pair of molding dies to transfer a transfer surface, and the molding material is maintained in a state where the transfer is maintained. A desired optical lens is formed by cooling. Here, as the molding material for the optical lens, a molding material such as glass or plastic is used.

  Here, as will be described later, the parallel light beam from the autocollimator 30 is projected onto the second flange surface 14b, and the parallel light beam reflected by the second flange surface 14b is point-imaged via the light receiving device 37 and the like. As observed. For this reason, for the second flange surface 14b, for example, a polishing pad or an abrasive is used for the optical lens 10 formed by an injection molding method or a press molding method in order to ensure sufficient reflection characteristics. A mirror surface treatment is applied by polishing to form a reflecting mirror surface 18. In addition, when the shaping | molding die which transfers the 2nd flange surface 14b accompanies sufficient surface accuracy, the 2nd flange surface 14b after shaping | molding can function as the reflective mirror surface 18 without performing a mirror surface process. . Here, the reflecting mirror surface 18 is formed so as to be orthogonal to the optical axis P1 of the optical lens 10 in this case.

  By forming the reflecting mirror surface 18 on the second flange surface 14 b, a reflecting surface having a sufficient area is secured, and the parallel light flux from the autocollimator 30 is reliably projected onto the reflecting mirror surface 18. Further, since the reflecting mirror surface 18 is formed at a position separated from the optical axis P1 of the optical lens 10, a point image reflected by the reflecting mirror surface 18 and observed through the light receiving device 37 or the like is displayed on the lens barrel 20. The inclination between the optical axis P0 and the optical axis P1 of the optical lens 10 appears clearly.

  In this embodiment, the flange surfaces 12b and 14b are formed outside the optical function surfaces 12a and 14a. For example, a sufficiently large edge portion is formed outside the optical function surfaces 12a and 14a. In some cases or when the optical lens has a sufficient outer diameter, the reflecting mirror surface may be formed in a region outside the optical function surfaces 12a and 14a without providing the flange surfaces 12b and 14b. In the present embodiment, the reflecting mirror surface 18 is formed over the entire outer periphery of the second flange surface 14b. However, the reflecting mirror surface 18 is formed only on the portion where the parallel light flux from the autocollimator 30 is projected. Also good.

  Next, when the lens barrel 20 including the optical lens 10 according to the embodiment of the present invention is assembled, the inclination between the optical axis P1 of the optical lens 10 incorporated in the lens barrel 20 and the optical axis P0 of the lens barrel 20 is described. The autocollimator 30 used for adjusting and verifying will be described. FIG. 2 is a schematic diagram illustrating a configuration of a general autocollimator.

  As shown in FIG. 2, the autocollimator 30 includes a light source 31, a target 32 that transmits a part of the light emitted from the light source 31, a half mirror 33 that reflects a part of the emitted light to the reflecting member 50, and a collimator lens. 34, and a support device 36 for adjusting the arrangement of the autocollimator optical system 35. In the measurement by the autocollimator 30, a reflecting member 50 such as a mirror, a light receiving device 37 including a light receiving element that receives reflected light, and a display device 38 such as a monitor that displays parallel light beams received by the light receiving device 37. And are used.

  When measuring the inclination of the measuring object 52 by the autocollimator 30, first, the emitted light from the light source 31 passes through a slit (not shown) provided in the target 32, and the transmitted light is branched by the half mirror 33. The The branched light is converted into a parallel light beam by the collimator lens 34, and the parallel light beam is projected onto the reflecting member 50 installed on the measurement object 52. Next, the parallel light beam reflected by the reflecting member 50 enters the collimator lens 34 and is collected, and is received by the light receiving device 37 disposed at the focal position of the collimator lens 34.

  As shown in FIG. 2, a parallel light beam 40 a is projected onto the reflecting member 50. Here, when the reflecting member 50 is not inclined, the reflected parallel light beam 40b is incident on the collimator lens 34 through the substantially same optical path as the projected parallel light beam 40a, and is collected and received. Light is received by the device 37. On the other hand, when the reflecting member 50 is tilted, it is incident on the collimator lens 34 via an optical path different from the optical path of the parallel light beam 40 a on which the parallel light beam 40 b ′ is projected, condensed, and received by the light receiving device 37. The Therefore, the point image observed through the light receiving device 37 or the like is a point image observed when the measuring object 52 on which the reflecting member 50 is installed is tilted and when the measuring object 52 is not tilted. Since the observation is performed in a state shifted from the position, the inclination of the measurement object 52 is measured.

  Next, a process for incorporating the optical lens 10 into the lens barrel 20 using the autocollimator 30 as described above will be described. FIGS. 3-8 is schematic explanatory drawing which shows the process at the time of incorporating an optical lens in a lens-barrel, respectively. 4 and 7 are partially enlarged views showing the main parts of FIGS. 3 and 6 in an enlarged manner, respectively.

  As shown in FIG. 3, when assembling the optical lens 10, the assembly jig 60 and the suction jig 70 are used together with the above-described autocollimator 30 and the like.

  The assembling jig 60 is used for various purposes, but when the optical lens 10 described here is assembled, it is mainly used for installing and fixing the lens barrel 20. The assembly jig 60 is provided with a receiving surface 62 with high processing accuracy and an opening 64 larger than the inner diameter of the lens barrel 20. Hereinafter, for convenience of explanation, on the cross-sectional view, the receiving surfaces located on both sides of the opening 64 are also referred to as first and second receiving surfaces 62a and 62b, respectively, but the first and second receiving surfaces 62a, 62b constitutes substantially the same plane. A fixing member 66 is provided on the first receiving surface 62a, and a positioning member (for example, a positioning pin (not shown) or the like) provided on the fixing member 66 includes the lens barrel 20 installed on the first receiving surface 62a. ) To be fixed at a predetermined position by the fixing member 66.

  The suction jig 70 is connected to a suction device (not shown), and the optical lens 10 is sucked to the suction surface 72 by a suction force acting on a suction hole (not shown) provided on the suction surface 72. The optical lens 10 can be moved through an operation by an operation device (not shown) or the like. The suction jig 70 is provided with alignment adjusting means 74, and the arrangement and inclination of the suction surface 72 are adjusted with respect to the receiving surface 62 of the assembly jig 60. 6 and 8 described later, a part of the suction jig 70 is omitted for convenience of display.

  When the optical lens 10 is assembled, in the first step, the alignment of the suction surface 72 of the suction jig 70 is adjusted with respect to the receiving surface 62 of the assembly jig 60 as shown in FIG. In this step, first, as shown in FIG. 3A, the reference mirror 80a is installed on the second receiving surface 62b, and the other reference mirror 80b is adsorbed on the adsorption surface 72. In each of the reference mirrors 80a and 80b, both surfaces are accurately formed in parallel. Here, in the opening 64 of the assembly jig 60, the reflection surfaces of the reference mirror 80a installed on the second receiving surface 62b and the reference mirror 80b sucked on the suction surface 72 are substantially parallel to each other. A suction jig 70 is arranged.

  In this state, as shown in FIG. 3B, alignment adjustment of the suction surface 72 is performed using the autocollimator 30 as follows. That is, the autocollimator 30 is installed so as to face the reflecting surfaces of the two reference mirrors 80a and 80b, and the arrangement thereof is adjusted by the support device 36. Then, the parallel light beam 42 a emitted from the autocollimator 30 is projected onto the reflection surfaces of the reference mirrors 80 a and 80 b, and the parallel light beam 42 b (or 42 b ′) reflected by the reflection surface is received by the light receiving device 37. Thereby, the observation image by the autocollimator 30 is displayed on the screen of the display device 38 as two point images 44a and 44b (or 44b ') as shown in FIG. 4, for example.

  Here, as shown in FIG. 4A, if the positions of the two point images 44a and 44b ′ are shifted from each other, the reflecting surfaces of the two reference mirrors 80a and 80b are not in a parallel state (receiving surface 62). Therefore, it is necessary to adjust the alignment of the suction surface 72. In this case, the alignment of the suction surface 72 is adjusted using the alignment adjusting means 74 while confirming the positions of the two point images 44 a and 44 b ′ displayed on the screen of the display device 38.

  4B, if the positions of the two point images 44a and 44b overlap each other, the reflecting surfaces of the two reference mirrors 80a and 80b are in a parallel state (receiving surface 62). And the suction surface 72 are in a parallel state), the alignment adjustment of the suction surface 72 ends. When a predetermined alignment accuracy is ensured, the first step is finished, and after removing the reference mirrors 80a and 80b, the second step is performed.

  In the second step, the lens barrel 20 is fixed to the assembly jig 60 as shown in FIG. In this step, first, as shown in FIG. 5A, the optical lens 10 is sucked onto the suction surface 72 of the suction jig 70. Here, since the optical lens 10 is attracted to the attracting surface 72 with the alignment adjusted, the optical axis P1 of the optical lens 10 is accurately disposed so as to be orthogonal to the receiving surface 62 of the assembly jig 60. The

  When the optical lens 10 is attracted, it is desirable that the optical lens 10 is transported by other transport means and is attracted to the suction jig 70 without moving the suction jig 70. On the other hand, if there is no error in the adjusted alignment due to the movement of the suction jig 70, the suction jig 70 moves, so that the optical lens 10 arranged in another place is sucked, and a predetermined position is obtained. You may make it arrange | position to.

  In this state, as shown in FIG. 5B, the lens barrel 20 is installed on the first receiving surface 62a of the assembling jig 60, and is moved to a predetermined position by the fixing member 66 via a positioning member (not shown). Fixed. A reference surface 22 that is exactly orthogonal to the optical axis P0 of the lens barrel 20 is provided at the end of the lens barrel 20, and the reference surface 22 of the lens barrel 20 is formed on the first receiving surface 62a of the assembly jig 60. The lens barrel 20 is fixed to the assembly jig 60 in the contacted state. Thus, the lens barrel 20 is accurately fixed so that the optical axis P0 of the lens barrel 20 is orthogonal to the receiving surface 62 of the assembly jig 60.

  Here, a lens frame 24 to which the optical lens 10 is attached is assembled in advance inside the lens barrel 20. As shown in FIG. 5C, a lens mounting surface 24a corresponding to the first flange surface 12b (including the cylindrical surface 16b) of the optical lens 10 is formed on the lens frame 24, and the lens mounting surface 24a. The adjustment margin required for adjusting the optical axis of the optical lens 10 is secured. Thus, the second process is completed, and the third process is performed.

  In the third step, as shown in FIG. 6A, the inclination of the optical axis P1 of the optical lens 10 arranged in the lens frame 24 is adjusted. In this step, first, as shown in FIG. 6A, the reference mirror 80 a is installed on the second receiving surface 62 b of the assembly jig 60. In this state, the inclination of the optical axis P1 of the optical lens 10 is adjusted using the autocollimator 30 as follows. That is, the autocollimator 30 is installed so as to face the reflecting surface of the reference mirror 80 a and the reflecting mirror surface 18 of the optical lens 10, and adjusted by the support device 36. Here, unlike the first step, the autocollimator 30 is disposed on the opposite side of the receiving surface 62 of the assembly jig 60. Then, the parallel light beam 46 a from the autocollimator 30 is projected onto the reflecting surface and the reflecting mirror surface 18 through the opening 64 of the assembly jig 60, and the parallel light beam 46 b (or 46 b ′) reflected by the reflecting surface and the reflecting mirror surface 18. Is received by the light receiving device 37. Thereby, the observation image by the autocollimator 30 is displayed on the screen of the display device 38 as two point images 48a and 48b (or 48b ') as shown in FIG. 7, for example.

  Here, as shown in FIG. 7A, when the positions of the two point images 48a and 48b ′ are shifted from each other, the reflecting surface and the reflecting mirror surface 18 are not in a parallel state (of the optical lens 10). This means that the optical axis P1 and the optical axis P0 of the lens barrel 20 are not in a parallel state), so that it is necessary to adjust the inclination of the optical axis P1 of the optical lens 10 disposed in the lens frame 24. In this case, while confirming the positions of the two point images 48a and 48b 'displayed on the screen of the display device 38, for example, as shown in FIG. Thus, the inclination of the optical axis P1 of the optical lens 10 is adjusted within the range of the adjustment allowance of the lens mounting surface 24a.

  On the other hand, as shown in FIG. 7B, when the positions of the two point images 48a and 48b overlap each other, the reflecting surface and the reflecting mirror surface 18 are in a parallel state (the optical axis P1 of the optical lens 10 and the mirror). This means that the optical axis P0 of the cylinder 20 is in a parallel state), so that the adjustment of the inclination of the optical axis P1 of the optical lens 10 is not required. Therefore, since a predetermined adjustment accuracy is ensured, the adhesive is filled between the first flange surface 12b (including the cylindrical surface 16b) and the lens mounting surface 24a, so that the lens frame 24 has an optical lens. 10 is mounted and fixed.

  Here, the inclination between the optical axis P 1 of the optical lens 10 and the optical axis P 0 of the lens barrel 20 is adjusted via the receiving surface 62 of the assembly jig 60. When assembling the lens frame 24, which is a separate part, inside the lens barrel 20, the assembly accuracy may not be ensured sufficiently, but the optical axis P 1 of the optical lens 10 and the optical axis P 0 of the lens barrel 20 Therefore, the influence of the assembly accuracy of the lens frame 24 on the incorporation of the optical lens 10 is mitigated. Thereby, the third step is completed, and the suction jig 70 is removed. In addition, when verifying assembly accuracy as needed, the following verification process is performed.

  In the verification process, as shown in FIG. 8A, the inclination of the optical axis P1 of the optical lens 10 incorporated in the lens barrel 20 is verified. In this step, as in the third step, the lens barrel 20 in which the optical lens 10 is incorporated is fixed to the assembly jig 60, and the autocollimator 30 is installed. The parallel light beam 49a from the autocollimator 30 is projected onto the reflecting surface and the reflecting mirror surface 18 of the reference mirror 80a, and the parallel light beam 49b (or 49b ′) reflected by the reflecting surface and the reflecting mirror surface 18 is received by the light receiving device 37. The observation image by the autocollimator 30 is confirmed on the screen of the display device 38.

  Here, as in the third step shown in FIG. 7A, when the positions of the two point images are shifted from each other, the reflecting surface and the reflecting mirror surface 18 are not in a parallel state (optical lens 10). The optical axis P1 of the lens barrel 20 and the optical axis P0 of the lens barrel 20 are not parallel to each other), and therefore, the inclination of the optical axis P1 of the optical lens 10 incorporated in the lens barrel 20 needs to be adjusted. In this case, while confirming the positions of the two point images displayed on the screen of the display device 38, for example, as shown in FIG. The inclination of the ten optical axes P1 is adjusted. In this case, it is desirable to use a curing retarding adhesive for bonding the optical lens 10 and the lens frame 24.

  On the other hand, as in the third step shown in FIG. 7B, when the positions of the two point images overlap each other, the reflecting surface and the reflecting mirror surface 18 are in a parallel state (the optical axis P1 of the optical lens 10). And the optical axis P0 of the lens barrel 20 are in a parallel state). Therefore, the verification process ends when the inclination of the optical axis P1 of the optical lens 10 is verified.

  Here, the inclination between the optical axis P 1 of the optical lens 10 and the optical axis P 0 of the lens barrel 20 includes, for example, the receiving surface 62 of the assembly jig 60, the suction surface 72 of the suction jig 70, and the lens barrel 20. The processing accuracy of the reference surface 22 and the like and the assembly accuracy of the lens frame 24 are affected. In the verification test by the applicants, etc., the optical lens 10 is assembled under the condition that the processing accuracy is within (1/60) ° and the assembly accuracy is within (2/60) °. The optical lens 10 could be incorporated within a range of accuracy that is not required after the verification of the adjustment of the optical axis P1. In addition, as the reflecting mirror surface 18, the second flange surface 14b having a width of about 1 mm with respect to the optical lens 10 having a maximum outer diameter of about 8 mm has an arithmetic average roughness (Ra) 20 nm corresponding to the optical functional surfaces 12a and 14a. Mirror finish to the extent. Thereby, the favorable reflection characteristic of the reflective mirror surface 18 was confirmed because the parallel light beam from the autocollimator 30 is specularly reflected without being diffused.

  According to the optical lens 10 of the present embodiment as described above, the reference surface formed as the flat reflecting mirror surface 18 is provided. Therefore, by measuring the reflected light reflected from the reference surface, the optical axis P1 of the optical lens 10 is measured. The direction is confirmed. Therefore, when the lens barrel 20 is assembled, the optical lens 10 can be incorporated into the lens barrel 20 while measuring the inclination of the optical axis P1 of the optical lens 10. For this reason, the inclination of the optical axis P1 of the optical lens 10 is adjusted in the state of being assembled in the lens barrel 20 without requiring the disassembly work of the lens barrel 20, and verified as necessary.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, this invention is not limited to the example which concerns. It is obvious for those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea described in the claims. It is understood that it belongs to.

  For example, in the description of the above embodiment, the case where the present invention is applied to the optical lens 10 which is an example of an optical element has been described. However, the present invention can be similarly applied to optical elements other than optical lenses, such as mirrors such as concave mirrors and convex mirrors, solid immersion lenses, solid immersion mirrors, and prisms. That is, even in an optical element other than the optical lens, by providing a reference surface formed as a flat reflecting mirror surface, the direction of the optical axis of the optical element is confirmed by measuring the reflected light reflected from the reference surface. . Therefore, when the optical unit is assembled, the optical element can be incorporated into the optical unit while measuring the inclination of the optical axis of the optical element in the optical unit.

  In the description of the above embodiment, the case where the optical lens 10 includes the reference surface (reflecting mirror surface 18) formed as a surface orthogonal to the optical axis P1 has been described. However, the present invention is not limited to an optical lens having a reference plane orthogonal to the optical axis, and can be similarly applied to, for example, an optical element having a reference plane inclined at a predetermined angle with respect to the optical axis. . For example, even when the reference plane is inclined at a predetermined angle with respect to the optical axis or the reference plane is provided on the side surface of the flange portion, by appropriately adjusting the arrangement angle of the autocollimator or jig with respect to the reference plane, The inclination of the optical axis of the optical element is adjusted and verified.

  In the description of the above embodiment, the inclination of the optical axis P1 of the optical lens 10 is adjusted while observing the point image of the reflected light reflected from the reference surface (reflecting mirror surface 18) of the optical lens 10 using the autocollimator 30. And explained the case of verification. However, the present invention is not limited to the case where an autocollimator is used, and can be similarly applied to a case where a measuring device such as an interferometer is used. For example, the inclination of the optical axis of the optical element in the optical unit is adjusted and verified while observing the state (interval, direction, etc.) of interference fringes of reflected light reflected from the reference surface of the optical element with an interferometer.

  In the description of the above embodiment, the case where the optical lens 10 is incorporated in the lens barrel 20 as an example of the optical unit has been described. However, the application of the present invention is not limited to this case. That is, for example, the present invention can be similarly applied to a case where an optical element is incorporated in an optical lens storage portion of an optical pickup device or a mobile phone with a camera function.

It is explanatory drawing which shows the optical lens which concerns on one Embodiment of this invention. It is a schematic diagram which shows the structure of a general autocollimator. It is a schematic explanatory drawing which shows the 1st process at the time of incorporating an optical lens in a lens barrel. FIG. 4 is a partially enlarged view showing an essential part of FIG. 3 in an enlarged manner. It is a schematic explanatory drawing which shows the 2nd process at the time of incorporating an optical lens in a lens barrel. It is a schematic explanatory drawing which shows the 3rd process at the time of incorporating an optical lens in a lens barrel. It is the elements on larger scale which expand and show the principal part of FIG. It is a schematic explanatory drawing which shows the verification process of the optical lens integrated in the lens barrel.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Optical lens 12a, 14a Optical function surface 12b, 14b Flange surface 18 Reflective mirror surface 20 Lens barrel 22 Reference surface 24 Lens frame 30 Autocollimator 40a, 40b, 42a, 42b, 46a, 46b, 49a, 49b Parallel light beam 60 Assembly jig 62 Reception surface 64 Opening portion 70 Suction jig 72 Suction surface 80a, 80b Reference mirror

Claims (10)

An optical functional surface for refracting or reflecting incident light; and
A reference surface formed as a flat reflecting mirror surface outside the optical function surface to indicate the direction of the optical axis;
An optical element comprising:   The optical element according to claim 1, wherein the optical element is formed as an optical lens.   The optical element according to claim 1, wherein the reference surface is a surface orthogonal to the optical axis.   The optical element according to claim 1, further comprising a flange portion outside the optical function surface, wherein the reference surface is formed on a surface constituting the flange portion.   The optical element according to claim 1, wherein the reference surface is formed with an arithmetic average roughness (Ra) of 20 nm or less.   The optical element according to claim 1, wherein the optical element is made of glass.   The optical element according to claim 1, wherein the optical element is made of plastic.   The substantially cylindrical surface which protrudes in the direction of the said optical axis coaxially with the said optical axis is formed in the back side of the said reference surface formed in the said flange part, The any one of Claims 4-7 characterized by the above-mentioned. An optical element according to any one of the above. Projecting projection light onto a reference surface formed on the optical element as a flat reflecting mirror surface to indicate the direction of the optical axis of the optical element;
Measuring reflected light reflected from the reference surface;
Adjusting the tilt of the optical axis of the optical element in the optical unit;
A method for assembling an optical unit comprising:   The method according to claim 9, further comprising: verifying an optical axis tilt of the optical element in the optical unit.

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