JP2012013968A - Manufacturing method of lens unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of an alignable lens unit in which floating of a lens or lens frame does not occur without the need of pressing the lens or the lens frame.SOLUTION: In assembling a lens unit 10, a lens 11 is disposed on a receiving surface 12s of a lens frame 12 and a lateral face 11t of the lens 11 is pushed by adjusting pins 13 in a direction mH perpendicular to a light axis AX to align the lens 11. The lateral face 11t of the lens 11 has a tapered shape, which is inclined in the direction of approaching the light axis AX as going away from the receiving surface 12s at least in a portion pushed for alignment of the lens. The taper angle is 5 to 45 degrees to the light axis AX. When the lateral face of the lens 11 is pushed by the adjusting pins 13 at alignment of the lens, a force acts on the lens 11 to press it against the receiving surface 12s.

Description

  The present invention relates to a method for manufacturing a lens unit, and for example, relates to a method for manufacturing a lens unit that performs lens alignment in the assembly of a lens unit of a camera.

  In assembling the lens unit, lens adjustment (so-called alignment) is performed in which the lens is decentered in parallel or tilted and decentered along the reference plane, thereby adjusting aberrations and ensuring optical performance. In the alignment, as shown in FIG. 10A, the adjustment pin 3 is moved by the actuator 4 to push the side surface (edge surface) 1f of the lens 1 to slightly move the lens 1 in the direction to be decentered. However, when the side surface 1f of the lens 1 is pressed, the lens 1 may tilt and float from the receiving surface (body mounting surface) 2s. In that case, there is a risk that the aberration cannot be adjusted properly or other aberrations may occur. 10A is an angle formed by the mounting surface 1s of the lens 1 and the receiving surface 2s of the ball frame 2. In FIG.

  In order to prevent the lens 1 from floating, there is a device that performs alignment while pressing the lens 1 against the receiving surface 2s by using a weight member 5 or a spring pressure as shown in FIG. It is proposed in Patent Document 1 and the like.

JP 2004-177422 A

  However, it is often difficult to align a lens unit including a plurality of lenses by the method described in Patent Document 1. This is because a general lens unit is composed of a plurality of lenses, and in order to ensure the overall optical performance, an optimum lens in consideration of aberration sensitivity is selected and alignment is performed. For example, as shown in FIG. 11A, when the lens 1 to be centered out of the three lenses 1, 1 </ b> A, 1 </ b> B is outside, it is easy to press the lens 1 using the weight member 5, When the lens 1 to be centered is inside (for example, when the lens 1A in FIG. 11A is aligned), it is difficult to configure the lens presser.

  Therefore, when the lens 1 to be aligned is inside, a spring 6 is added as a product part as shown in FIG. 11B, or a large opening is formed in a ball frame or the like as shown in FIG. It is necessary to provide a pressing mechanism including the weight member 5 and the like. However, such a configuration may increase the cost of the lens unit and insufficient strength of the lens frame.

  The present invention has been made in view of such a situation, and an object of the present invention is to provide a method of manufacturing a lens unit capable of aligning without causing the lens or the lens frame to float without pressing the lens or the lens frame. It is to provide.

  In order to achieve the above object, a method of manufacturing a lens unit according to a first aspect of the present invention includes a lens or a ball frame holding a lens disposed on a receiving surface, and the side surface of the lens or the side surface of the lens frame is an optical axis. A method of manufacturing a lens unit that performs alignment by pushing in a vertical direction or substantially vertical direction with respect to the lens, wherein the side surface of the lens or the side surface of the lens frame is at least a portion that is pressed during alignment. The taper shape is inclined in a direction approaching the optical axis of the lens as the distance from the lens increases, and the taper angle is not less than 5 degrees and not more than 45 degrees with respect to the optical axis of the lens.

  The method for manufacturing a lens unit according to a second aspect of the invention is characterized in that, in the first aspect, alignment is performed by pressing a side surface of the lens or a side surface of the lens frame with an adjustment pin driven by an actuator.

  The lens unit manufacturing method according to a third aspect of the present invention is characterized in that, in the first or second aspect of the invention, the side surface of the lens or the side surface of the lens frame has a peripheral surface shape of a truncated cone.

  According to a fourth aspect of the present invention, there is provided the lens unit manufacturing method according to the first or second aspect, wherein the tapered shape is provided only at a portion where the side surface of the lens or the side surface of the lens frame is pressed during alignment. To do.

  According to a fifth aspect of the present invention, there is provided a lens unit manufacturing method according to any one of the first to fourth aspects, wherein the lens is a plastic molded lens.

  According to a sixth aspect of the present invention, there is provided a lens unit manufacturing method according to any one of the first to fourth aspects, wherein the lens is a glass molded lens.

  According to the present invention, the side surface of the lens or the side surface of the lens frame is configured to have a tapered shape that is inclined at a predetermined angle in a direction approaching the optical axis as the distance from the receiving surface increases at least in a portion that is pushed during alignment. For this reason, when the side surface of the lens or the side surface of the lens frame is pressed during alignment, a force that presses the lens or the lens frame against the receiving surface acts. Therefore, it is not necessary to provide a separate pressing mechanism, and it is possible to perform alignment that does not cause the lens or the lens frame to float without pressing the lens or the lens frame. For example, even if the lens you want to align is inside the lens unit, there is no need to add a spring as a product part or to provide a holding mechanism with a large opening in a ball frame, etc. There is no risk that the cost will increase or the strength of the ball frame will be insufficient.

FIG. 3 is a cross-sectional view of a main part schematically illustrating the alignment operation of the lens according to the first embodiment. The figure which shows typically the lens unit in the centering operation | movement of FIG. The flowchart which shows the manufacturing method of the lens unit which concerns on 1st Embodiment. The graph which shows the inclination of the lens which generate | occur | produces by the alignment operation | movement of 1st Embodiment. FIG. 6 is a cross-sectional view of a main part showing another lens holding structure applicable to the first embodiment. Sectional drawing which shows the principal part which shows the other adjustment pin applicable to 1st Embodiment. FIG. 6 is an external view showing another to-be-aligned lens applicable to the first embodiment. FIG. 6 is an external view showing another to-be-aligned lens applicable to the first embodiment. Sectional drawing which shows typically the alignment operation | movement of the ball frame in 2nd Embodiment. Sectional drawing which shows typically the subject at the time of alignment, and the prior art for solving it. Sectional drawing which shows typically the lens unit to which a prior art is applied.

  A lens unit manufacturing method and the like embodying the present invention will be described below with reference to the drawings. In addition, the same code | symbol is mutually attached | subjected to the part which is the same in each embodiment etc., and the corresponding part, and duplication description is abbreviate | omitted suitably.

  FIG. 1 schematically shows the alignment operation of the lens 11 in the first embodiment, and FIG. 2 schematically shows the lens unit 10 during the alignment operation. 2A is a plan view seen from above the lens 11, and FIG. 2B is a longitudinal sectional view showing the main part of the entire lens unit 10 (note that the lens surface is simplified as a plane). .) As shown in FIG. 2, the lens unit 10 includes three lenses 11, 11 </ b> A, and 11 </ b> B and a ball frame that holds each lens. Here, a case where the lens 11 arranged inside the lens unit 10 is aligned will be described as an example, and a manufacturing method of the lens unit 10 will be described using the flowchart of FIG.

  First, a lens (centered lens) 11 to be aligned is placed in the lens frame 12 (# 10), and an ultraviolet curable adhesive is applied to the lens 11 and the lens frame 12 (# 20). The ball frame 12 is attached to the aligning device including the adjustment pin 13 and the actuator 14 (# 30), and the adjustment pin 13 is set on the lens 11 from four directions as shown in FIG. 2 (# 40). Error information (eccentricity, aberration, etc.) is measured (# 50), and an adjustment amount is calculated from the obtained error information (# 60). The actuator 14 moves the adjustment pin 13 in the arrow mH direction (FIG. 1) to adjust the position of the lens 11 (# 70), and the error information after adjustment is measured (# 80). The above processing (# 60 to # 90) is repeated until the adjustment is completed. When the adjustment is completed, the adhesive is irradiated with light (ultraviolet light or the like) to cure the adhesive (# 100). Fixing of the lens 11 aligned at an appropriate position on the receiving surface (body mounting surface) 12s of the ball frame 12 is completed by curing the adhesive.

  In the position adjustment (# 70) of the lens 11 arranged on the receiving surface 12s of the ball frame 12, the side surface (edge surface) 11t of the lens 11 is perpendicular to the optical axis AX by the adjustment pin 13 driven by the actuator 14. Alignment is performed by pushing on (which may be a substantially vertical direction. Here, the direction is parallel to the attachment surface 11s and the receiving surface 12s). The side surface 11t of the lens 11 has a circular truncated cone shape. That is, the side surface 11t of the lens 11 has a tapered shape that is inclined in a direction approaching the optical axis AX of the lens 11 as the distance from the receiving surface 12s of the ball frame 12 (or the mounting surface 11s of the lens 11) increases. The angle θ (FIG. 1) is set to 5 degrees or more and 45 degrees or less with respect to the optical axis AX of the lens 11.

  Since the normal lens side surface has a cylindrical shape, when the lens side surface is pushed from the lateral direction, the lens may float as described above (FIG. 10A). Even if the centering is performed while measuring the decentration aberration in a state where the lens is floating, an appropriate optical performance cannot be obtained. In the first embodiment, since the side surface 11t of the lens 11 has a tapered shape that is inclined in a direction approaching the optical axis AX of the lens 11 as the distance from the receiving surface 12s increases, the side surface 11t of the lens 11 is aligned during alignment. Is pushed with the adjusting pin 13, a force for pressing the lens 11 against the receiving surface 12s is applied. For this reason, it is possible to maintain the surface contact state between the mounting surface 11 s of the lens 11 and the receiving surface 12 s of the ball frame 12 without providing a separate pressing mechanism and pressing the lens 11.

  Therefore, according to the first embodiment, it is possible to perform alignment while maintaining a state in which the lens 11 does not float with a simple configuration. The lens 11 to be aligned is located inside the lens unit 10 as shown in FIG. 2 (B), but a spring is added as a product part (FIG. 11 (B)), or a large opening in a ball frame or the like. It is not necessary to provide a pressing mechanism by providing a portion (FIG. 11C), so there is no possibility that the cost of the lens unit 10 or the like will be increased and the strength of the ball frame 12 or the like will be insufficient.

  Even when the side surface 11t of the lens 11 is tapered as described above, the magnitude of the effect of pressing the lens 11 against the ball frame 12 varies depending on the taper angle θ (FIG. 1). FIG. 4 shows the relationship between the taper angle θ of the side surface 11t of the lens 11 and the generated tilt angle α (the angle formed by the mounting surface 11s of the lens 11 and the receiving surface 12s of the ball frame 12). It can be seen from the graph of FIG. 4 that the taper angle θ needs to be 5 degrees or more in order to set the allowable value of the inclination angle α to 0.5 minutes. That is, when the taper angle θ is 5 degrees or more, the inclination angle α can be suppressed to 0.5 minutes or less.

  Therefore, the taper angle θ is preferably 5 degrees or more and 45 degrees or less with respect to the optical axis AX of the lens 11. When the taper angle θ is less than 5 degrees, the effect of pressing the lens 11 against the ball frame 12 cannot be sufficiently obtained. When the taper angle θ exceeds 45 degrees, the load applied to the adjustment pin 13 is increased, and the adjustment pin 13 is distorted, and the fine movement accuracy during alignment is deteriorated. When the taper angle θ is set to 5 ° to 45 °, the balance between the effect of suppressing the floating of the lens 11 during alignment and the fine movement accuracy of the lens 11 during alignment is improved.

  Although the first embodiment can be realized with a simple configuration in which the side surface 11t of the lens 11 is tapered as described above, the lens 11, the ball frame 12, the aligning device (adjustment pin 13). , Actuator 14 etc.), alignment operation and the like are not particularly limited. For example, a plastic molded lens or a glass molded lens can be used as the lens 11 that is an aligned lens. Further, the moving direction of the lens 11 at the time of alignment is not particularly limited, and as shown in FIG. 2 (A), the adjustment pin 13 is arranged at four equal positions in the circumferential direction around the optical axis AX. You may comprise so that it may push from 4 directions, and you may comprise so that it may push from 3 directions with the adjustment pin 13 arrange | positioned in the circumferentially equivalent position centering on the optical axis AX. In the first embodiment, since it is assumed that alignment is performed with all the adjustment pins 13 always in contact with the lens 11, all adjustments are made on the side surface 11t of the lens 11 during alignment. A downward force is always applied from the pin 13.

  In the first embodiment, the mounting surface 11s of the lens 11 and the receiving surface 12s of the ball frame 12 are both planar, but at least one surface may be curved. Examples of the curved surface shape include a spherical shape and a truncated cone shape. For example, as shown in FIG. 5, a part of the lens surface may be used as a mounting surface 11 s, and alignment may be performed on the planar receiving surface 12 s, and the ring contact is made at the edge of the ball frame 12. You may make it align by (it shows with a broken line). Thus, by making at least one surface into a curved surface shape, alignment by tilt eccentricity along the curved surface can be performed.

  In the first embodiment, it is assumed that a cylindrical adjustment pin 13 (for example, a diameter of 2 mm and a length of 10 mm) is used, but the tip shape of the adjustment pin 13 may be a curved surface as shown in FIG. Good. Examples of the curved surface shape include a spherical shape and a cylindrical surface shape. If the tip of the adjustment pin 13 is curved, it will be slippery due to point contact with the side surface 11t of the lens 11, so that the tip of the adjustment pin 13 will not be caught on the side surface 11t, and stable high-precision alignment is possible. It becomes.

  FIG. 7 and FIG. 8 show the appearances of other aligned lenses 31 and 41 applicable to the first embodiment. 7 and 8, (A) is a plan view of the lenses 31 and 41, and (B) is a front view of the lenses 31 and 41. In the first embodiment, it is assumed that the side surface 11t has a truncated cone-shaped lens 11. However, as shown in FIG. 7, the portion pushed by the adjustment pin 13 (FIG. 2 and the like) during alignment is tapered. The lens 31 formed as a convex portion of the shape may be used, or as shown in FIG. 8, the lens 41 in which the portion pushed by the adjustment pin 13 during alignment is formed as a concave portion having a tapered shape may be used. Good.

  That is, as shown in FIGS. 7 and 8, only the portions (ie, the side surfaces 31t and 41t) that are pressed during alignment in the cylindrical lenses 31 and 41 having the side surfaces (edge surfaces) 31f and 41f are set to the tapered shape. (31s, 41s: mounting surface). From this point of view, it is preferable that the side surface of the centered lens has a tapered shape that is inclined in a direction approaching the lens optical axis as it moves away from the receiving surface at least in a portion to be pressed during alignment, and the taper angle is determined by the lens optical axis. Is preferably 5 to 45 degrees. In addition, the surface shape of the portion to be pushed during alignment may be a flat surface or a curved surface formed of a part of a truncated cone.

  FIG. 9 schematically shows the aligning operation of the ball frame 22 and the lens unit 20 during the aligning operation in the second embodiment (note that the lens surface is simplified as a plane). As shown in FIG. 9, the lens unit 20 includes three lenses 21, 21 </ b> A, and 21 </ b> B and a ball frame that holds each lens. Here, the manufacturing method of the lens unit 20 will be described by taking as an example a case where the ball frame 22 holding the lens 21 arranged inside the lens unit 20 is aligned. Since operations other than alignment in the manufacturing method of the second embodiment can be performed in the same manner as in the first embodiment (FIG. 3), description thereof is omitted.

  In the position adjustment of the ball frame 22 arranged on the receiving surface 23s of the ball frame 23 (for example, a fixed cylinder), the side surface (edge surface) 22t of the ball frame 22 is moved with respect to the optical axis AX by the adjustment pin 13 driven by the actuator 14. Alignment is performed by pushing in the vertical direction mH (which may be a substantially vertical direction. Here, the direction is parallel to the attachment surface 22s and the receiving surface 23s). The side surface 22t of the ball frame 22 has a peripheral surface shape of a truncated cone. That is, the side surface 22t of the ball frame 22 has a tapered shape that is inclined in a direction approaching the optical axis AX of the ball frame 22 as the distance from the receiving surface 23s of the ball frame 23 (or the mounting surface 22s of the ball frame 22) increases. The taper angle θ is set to 5 degrees or more and 45 degrees or less with respect to the optical axis AX of the ball frame 22.

  Since the normal side surface of the lens frame has a cylindrical shape, when the side surface of the lens frame is pushed from the lateral direction, the lens frame may float as described above (FIG. 10A). Even if the alignment is performed while measuring the decentration aberration in a state where the ball frame is floating, an appropriate optical performance cannot be obtained. In the second embodiment, since the side surface 22t of the lens frame 22 has a tapered shape that is inclined in a direction approaching the optical axis AX of the lens frame 22 as the distance from the receiving surface 23s increases, the lens frame 22 is aligned during alignment. When the side surface 22t is pushed with the adjusting pin 13, a force for pressing the ball frame 22 against the receiving surface 23s is applied. For this reason, it is possible to maintain the surface contact state between the mounting surface 22 s of the ball frame 22 and the receiving surface 23 s of the ball frame 23 without providing a separate pressing mechanism and pressing the ball frame 22.

  Therefore, according to the second embodiment, it is possible to perform alignment while maintaining a state in which the ball frame 22 does not float with a simple configuration. As shown in FIG. 9, the ball frame 22 to be aligned is inside the lens unit 20, but a spring is added as a product part (FIG. 11B), or a large opening is formed in the ball frame or the like. Since there is no need to provide a pressing mechanism (FIG. 11C), there is no possibility that the cost of the lens unit 20 and the like and the strength of the ball frame 23 and the like will be insufficient.

  Even when the side surface 22t of the ball frame 22 is tapered, the magnitude of the effect of pressing the ball frame 22 against the ball frame 23 differs depending on the taper angle θ. As described above (FIG. 4), if the taper angle θ is set to 5 degrees or more, the inclination angle α can be suppressed to 0.5 minutes or less, so the taper angle θ is set to the optical axis AX of the ball frame 22. On the other hand, it is preferably 5 degrees or more and 45 degrees or less. When the taper angle θ is less than 5 degrees, the effect of pressing the ball frame 22 against the ball frame 23 cannot be sufficiently obtained. When the taper angle θ exceeds 45 degrees, the load applied to the adjustment pin 13 is increased, and the adjustment pin 13 is distorted, and the fine movement accuracy during alignment is deteriorated. When the taper angle θ is set to 5 ° to 45 °, the balance between the effect of suppressing the float of the ball frame 22 during alignment and the fine movement accuracy of the ball frame 22 during alignment is good.

  Although the second embodiment can be realized with a simple configuration in which the side surface 22t of the ball frame 22 is tapered as described above, the ball frame 22, the ball frame 23, the alignment device (adjustment) There are no particular restrictions on the pin 13, the actuator 14, etc.) and the alignment operation. For example, as the lens 21 fixed to the ball frame 22, a plastic molded lens or a glass molded lens can be used. Further, the moving direction of the ball frame 22 at the time of alignment is not particularly limited, and as with the first embodiment, the adjustment pins 13 are arranged at four equal positions in the circumferential direction around the optical axis AX. It may be configured to be pressed from four directions (FIG. 2A), and is configured to be pressed from three directions with the adjustment pin 13 disposed at a three-divided position in the circumferential direction around the optical axis AX. May be. In the second embodiment, since it is assumed that alignment is performed with all the adjustment pins 13 always in contact with the ball frame 22, all the side surfaces 22t of the ball frame 22 during alignment are all on the side 22t. A downward force is always applied from the adjusting pin 13.

  In the second embodiment, the mounting surface 22s of the ball frame 22 and the receiving surface 23s of the ball frame 23 are both planar, but at least one surface may be curved. Examples of the curved surface shape include a spherical shape and a truncated cone shape. For example, the mounting surface 22s may be formed of a part of a spherical surface, and alignment may be performed on the planar receiving surface 23s, or alignment may be performed in a state where the edge of the ball frame 23 is in an annular contact. You may do it. Thus, by making at least one surface into a curved surface shape, alignment by tilt eccentricity along the curved surface can be performed.

  In the second embodiment, it is assumed that a cylindrical adjustment pin 13 (for example, a diameter of 2 mm and a length of 10 mm) is used, but the adjustment pin is the same as in the first embodiment (FIG. 6). The tip shape of 13 may be a curved surface shape. Examples of the curved surface shape include a spherical shape and a cylindrical surface shape. If the tip of the adjustment pin 13 has a curved surface, it will be slippery due to point contact with the side surface 22t of the ball frame 22, so that the tip of the adjustment pin 13 will not be caught on the side surface 22t, and stable high-precision alignment will be achieved. It becomes possible.

  In the second embodiment, it is assumed that the side 22t has a frustum-shaped ball frame 22. However, as in the above-described aligned lenses 31 and 41 (FIGS. 7 and 8), adjustment is performed during alignment. You may use the ball frame in which the part pressed with the pin 13 (FIG. 2 etc.) was formed as a taper-shaped convex part or a recessed part. That is, only the part pushed at the time of alignment is good also as the said taper shape in the ball frame whose side surface (edge surface) is cylindrical shape. From this point of view, it is preferable that the side surface of the lens frame holding the aligned lens has a tapered shape that is inclined in a direction approaching the lens optical axis as the distance from the receiving surface increases, at least in a portion that is pressed during alignment. The angle is preferably 5 to 45 degrees with respect to the lens optical axis. In addition, the surface shape of the portion to be pushed during alignment may be a flat surface or a curved surface formed of a part of a truncated cone.

DESCRIPTION OF SYMBOLS 10 Lens unit 11 Lens 11t Side surface 11s Mounting surface 12 Ball frame 12s Receiving surface 13, 13A Adjustment pin 14 Actuator 20 Lens unit 21 Lens 22 Ball frame 22t Side surface 22s Mounting surface 23 Ball frame 23s Receiving surface 31 Lens 31f, 31t Side surface 31s Installation Surface 41 Lens 41f, 41t Side surface 41s Mounting surface θ Taper angle α Tilt angle AX Optical axis

Claims (6)

A lens unit or a lens frame that holds the lens is disposed on a receiving surface, and the lens unit performs alignment by pressing the side surface of the lens or the side surface of the lens frame in a direction perpendicular or substantially perpendicular to the optical axis. A manufacturing method comprising:
The side surface of the lens or the side surface of the lens frame has a tapered shape that is inclined in a direction approaching the optical axis of the lens as it moves away from the receiving surface at least in a portion that is pressed during alignment, and the taper angle is the lens. A method of manufacturing a lens unit, wherein the angle is 5 degrees or more and 45 degrees or less with respect to the optical axis.   2. The method of manufacturing a lens unit according to claim 1, wherein alignment is performed by pressing a side surface of the lens or a side surface of the lens frame with an adjustment pin driven by an actuator.   3. The method of manufacturing a lens unit according to claim 1, wherein a side surface of the lens or a side surface of the lens frame has a peripheral surface shape of a truncated cone.   3. The method of manufacturing a lens unit according to claim 1, wherein the tapered shape is provided only in a portion where a side surface of the lens or a side surface of the lens frame is pressed during alignment.   The method for manufacturing a lens unit according to claim 1, wherein the lens is a plastic molded lens.   The method for manufacturing a lens unit according to claim 1, wherein the lens is a glass molded lens.

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