Lens unit

Abstract

To solve the problem in which: in a lens unit, drop-off of burr during adjustment of the accuracy of position in an optical axis direction of a lens may adversely affect the adjustment.SOLUTION: A lens unit comprises a plurality of lenses including a first lens 302 and a second lens 303, a lens barrel 20 that houses the plurality of lenses, and a hold-down member 40 that is provided between the first lens and the second lens. The hold-down member has: a cylindrical side wall part 41 that is centered on an optical axis of the plurality of lenses; a contact surface 410 that is located at an end on one end side of the side wall part in a direction along the optical axis and in contact with the first lens; a holding part 42 that is provided on the other end side of the side wall part in the direction along the optical axis and in contact with the second lens to hold the second lens; a coupling part 412 that is provided along the outer periphery on the other end side of the side wall part and screw-couples to a first area of an inner peripheral wall surface of the lens barrel; and a connection part forming surface that is provided with a connection part 43 to which a tool for rotating the hold-down member around the optical axis is connected, and is different from the contact surface.SELECTED DRAWING: Figure 3B

Description

[Technical Field]

[0001] The present invention relates to a lens unit. [Background technology]

[0002] Conventionally, lens units have been known in which the position of a lens in a fixed barrel in the optical axis direction is adjusted using an adjustment tool during manufacturing. Patent Document 1 discloses a lens unit having a fixed barrel, a lens held in the fixed barrel via a holding member, and a pressing member that presses the lens against the holding member in the optical axis direction. The adjustment tool is inserted into a hole formed in the pressing member and engages with an engaging portion of the holding member. By rotating the adjustment tool around the optical axis, the holding member is rotated relative to the fixed barrel, and the position of the lens held by the holding member in the optical axis direction is adjusted. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-90252 Summary of the Invention [Problem to be solved by the invention]

[0004] However, if a burr falls off during adjustment, depending on the location to which the fallen burr adheres, there is a risk that this may adversely affect the adjustment of the positional accuracy of the lens in the optical axis direction. [Means for solving the problem]

[0005] According to one embodiment, the lens unit includes a plurality of lenses including a first lens and a second lens, a lens barrel housing the plurality of lenses, and a presser member provided between the first lens and the second lens. The presser member has a cylindrical side wall portion centered on the optical axis of the plurality of lenses, a contact surface located at one end of the side wall portion in a direction along the optical axis and in contact with the first lens, a holding portion provided at the other end of the side wall portion in the direction along the optical axis and in contact with the second lens to hold the second lens, a coupling portion provided along the outer periphery of the other end of the side wall portion and threadedly coupled to a first region of an inner peripheral wall surface of the lens barrel, and a coupling portion forming surface, different from the contact surface, on which a coupling portion to which a tool for rotating the presser member about the optical axis is connected is provided. [Effects of the Invention]

[0006] According to the present disclosure, the lens can be positioned within the lens barrel with high precision. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a perspective view of the appearance of a lens unit according to an embodiment. [Figure 2] FIG. 2 is a cross-sectional view of the lens unit taken along line AA in FIG. [Figure 3A] FIG. 3A is an external perspective view of the pressing member. [Figure 3B] FIG. 3B is a side view of the pressing member. [Figure 4A] FIG. 4A is a cross-sectional view of a pressing member of a first modified example. [Figure 4B] FIG. 4B is a cross-sectional view of another example of a pressing member of the first modified example. [Figure 5] FIG. 5 is an external view of a lens unit according to a second modified example. DETAILED DESCRIPTION OF THE INVENTION

[0008] <Embodiment> Hereinafter, the lens unit according to the embodiment will be described in detail with reference to the drawings.

[0009] Fig. 1 is an external perspective view of lens unit 10 according to an embodiment, and Fig. 2 is a cross-sectional view of lens unit 10 taken along line AA in Fig. 1. Lens unit 10 includes a lens barrel 20, an optical member 30, and a retaining member 40. Lens unit 10 is used by being attached to, for example, a measuring instrument or an imaging device.

[0010] For convenience of explanation, an orthogonal coordinate system is set up, which is made up of an x-axis parallel to the optical axis Ax of the optical member 30, a z-axis perpendicular to the x-axis and extending in the vertical direction of the paper surface of Fig. 2, and a y-axis perpendicular to the x-axis and z-axis. In the following explanation, the positive side of the x-axis may be referred to as the front, and the negative side of the x-axis may be referred to as the rear.

[0011] <Optical member 30> The optical member 30 is housed inside the lens barrel 20, which will be described later. The optical member 30 is composed of multiple lenses 301, 302, 303, 304, 305, 306, 307, and 308 arranged along the x-axis inside the lens barrel 20. The eight lenses 301, 302, 303, 304, 305, 306, 307, and 308 are arranged in the above order from the positive side of the x-axis. As described above, the lenses 301, 302, 303, 304, 305, 306, 307, and 308 are arranged so that the optical axis Ax is parallel or approximately parallel to the x-axis. The number of lenses included in the optical member 30 is not limited to eight, and may be seven or less or nine or more, as long as it is two or more.

[0012] Lenses 301 and 302 are included in a first lens group 31. The diameters of lenses 301 and 302 are equal to or approximately equal to each other. Lenses 303, 304 and 305 are included in a second lens group 32. The diameters of lenses 303, 304 and 305 are equal to or approximately equal to each other. Lenses 306, 307 and 308 are included in a third lens group 33. The diameters of lenses 306, 307 and 308 are equal to or approximately equal to each other.

[0013] The diameters of lenses 301 and 302 included in first lens group 31 are larger than the diameters of lenses 303, 304, and 305 included in second lens group 32. The diameters of lenses 306, 307, and 308 included in third lens group 33 are larger than the diameters of lenses 303, 304, and 305, but smaller than the diameters of lenses 301 and 302.

[0014] The number of lenses included in each of the first lens group 31, the second lens group 32, and the third lens group 33 is not limited to the above example.

[0015] <Telescope tube 20> The lens barrel 20 accommodates the optical element 30 therein. The lens barrel 20 is a hollow cylinder whose central axis is the optical axis Ax of the accommodated optical element 30. The lens barrel 20 is made of, for example, a resin material or a metal material. The lens barrel 20 is formed with a first accommodation section 21, a second accommodation section 22, and a third accommodation section 23, which are spaces for accommodating the optical element 30 described below. Furthermore, through holes 60 and 70 are formed in the side walls of the lens barrel 20.

[0016] The first housing section 21 is formed near the end of the lens barrel 20 on the +x-axis side. The third housing section 23 is formed near the end of the lens barrel 20 on the -x-axis side. The second housing section 22 is formed between the first housing section 21 and the third housing section 23. The +x-axis side of the second housing section 22 is connected to the -x-axis side of the first housing section 21. The -x-axis side of the second housing section 22 and the +x-axis side of the third housing section 23 are connected via a connection space 24. The first housing section 21, the second housing section 22, and the third housing section 23 each have a different diameter.

[0017] <First storage section 21> Lenses 301 and 302 included in first lens group 31 and a retaining member 40, which will be described later, are accommodated in first housing section 21. Specifically, lenses 301 and 302 and a retaining member 40, which will be described later, are arranged in this order from the positive side of the x-axis in first housing section 21. The diameter of first housing section 21, i.e., the inner diameter of lens barrel 20 at the position where first housing section 21 is formed, is equal to or approximately equal to the diameters of lenses 301 and 302.

[0018] The lens 301 is pressed rearward from its front side (positive x-axis side) by the front pressing ring 34. The rear end (negative x-axis side) of the lens 301 and the front end (positive x-axis side) of the lens 302 are partially in contact with each other. A portion of the rear end of the lens 302 is in contact with the front side of the pressing member 40.

[0019] A part of the rear side of the pressing member 40 contacts a part of the front end of the lens 303 included in the second lens group 32. In other words, the pressing member 40 is disposed at the rear end of the first housing section 21. In the following description, the lens 302 will be referred to as the first lens 302, and the lens 303 will be referred to as the second lens 303.

[0020] Near the rear end of first housing section 21, a through-hole 60 is formed that penetrates the wall surface of barrel 20. That is, through-hole 60 is formed in a position that overlaps with the position where pressing member 40 is disposed in the x-axis direction. Details of through-hole 60 will be described later. Furthermore, the vicinity of the rear end of first housing section 21 refers to a position that is spaced away from the rear end of first housing section 21 on the positive x-axis side, depending on the shape of pressing member 40, which will be described later.

[0021] A first region 203 at the rear end of the inner circumferential wall surface 202 of the first housing portion 21 is formed with a female thread. A holding member 40 (described later) is attached to the inside of the first housing portion 21 by being screwed into the female thread formed in the first region 203. A second region 204 (see FIG. 3B) is formed at the rear end of the inner circumferential wall surface 202, closer to the positive x-axis side than the first region 203. The holding member 40 (described later) is fixed inside the first housing portion 21 by fitting into the second region 204.

[0022] <Second storage section 22> In second housing section 22, lenses 303, 304, and 305 included in second lens group 32 are arranged in this order from the positive x-axis side. The diameter of second housing section 22, i.e., the inner diameter of lens barrel 20 at the position where second housing section 22 is formed, is equal to or approximately equal to the diameters of lenses 303, 304, and 305. Because the diameters of lenses 303, 304, and 305 are smaller than the diameters of lenses 301 and 302, the diameter of second housing section 22 is smaller than the diameter of first housing section 21.

[0023] The front side of lens 303 protrudes from second housing portion 22. A portion of the front end of lens 303 is in contact with the rear side of pressing member 40 housed in first housing portion 21. The rear end of lens 303 and the front end of lens 304 are in partial contact with each other. The rear end of lens 304 and the front end of lens 305 are in partial contact with each other. The rear end of lens 305 is in partial contact with rear wall surface 220 of second housing portion 22.

[0024] <Third storage section 23> The third housing section 23 houses lenses 306, 307, and 308 included in the third lens group 33, and hollow cylindrical spacer members 50 and 51. Specifically, the lenses 306, 307, and 308 are arranged in this order from the positive x-axis side. The spacer member 50 is disposed between the lenses 306 and 307. The spacer member 51 is disposed between the lenses 307 and 308. The diameter of the third housing section 23, i.e., the inner diameter of the lens barrel 20 at the position where the third housing section 23 is formed, is equal to or approximately equal to the diameters of the lenses 306, 307, and 308 and the outer diameter of the spacer members 50 and 51.

[0025] As described above, the diameters of the lenses 306, 307, and 308 are larger than the diameters of the lenses 303, 304, and 305 of the second lens group 32, and smaller than the diameters of the lenses 301 and 302 of the first lens group 31. Therefore, the diameter of the third housing portion 23 is larger than the diameter of the second housing portion 22, and smaller than the diameter of the first housing portion 21.

[0026] The front side of lens 306 is in partial contact with the front wall surface 230 of the third housing section 23. The rear side of lens 306 is in partial contact with the front side of spacer member 50. The front side of lens 307 is in partial contact with the rear side of spacer member 50, and the rear side of lens 307 is in partial contact with the front side of spacer member 51. The front side of lens 308 is in partial contact with the rear side of spacer member 51. Lens 308 is pressed forward from the rear side by rear press ring 35.

[0027] In the range of lens barrel 20 where third housing section 23 is formed, a through-hole 70 is formed through the wall surface of lens barrel 20. Specifically, through-hole 70 is formed in a position in the x-axis direction that overlaps with the position where spacer member 50 is disposed. Details of through-hole 70 will be described later.

[0028] Furthermore, the through-hole 70 may be formed at a position in the x-axis direction that overlaps with the position at which the spacer member 51 is disposed. Furthermore, the through-hole 70 may be provided at a position in the x-axis direction that overlaps with at least one of the positions at which the lenses 306, 307, and 308 are disposed, rather than at the position at which the spacer members 50 and 51 are disposed.

[0029] <Through hole 60> As described above, the through hole 60 is formed at a position in the x-axis direction that overlaps with the position at which the pressing member 40 is disposed. Specifically, the through hole 60 is formed at a position in the x-axis direction that overlaps with the position at which a fixing portion 413 (see FIGS. 3A and 3B), which will be described later, of the pressing member 40 is formed. More specifically, the position of the through hole 60 overlaps with the second region 204 of the inner circumferential wall surface 202 of the first accommodating portion 21 in the x-axis direction.

[0030] The through-hole 60 is used to accurately assemble the lenses 301, 302 into the first housing portion 21 during the manufacturing process of the lens unit 10. Specifically, the pressing member 40 is aligned using a jig or the like inserted into the through-hole 60. Thereafter, an adhesive or the like is applied to the inside of the through-hole 60, and the pressing member 40 is fixed in the first housing portion 21.

[0031] A plurality of through holes 60 are formed along the circumferential direction of lens barrel 20. For example, three through holes 60 are provided at intervals of 120° along the circumferential direction of lens barrel 20. The number of through holes 60 is not limited to three, and may be four or more.

[0032] Through-hole 60 penetrates outer peripheral wall surface 201 of barrel 20 and inner peripheral wall surface 202 of first housing portion 21. More specifically, through-hole 60 penetrates outer peripheral wall surface 201 and second region 204 of first housing portion 21. In other words, through-hole 60 is formed along the radial direction of barrel 20. The radial direction of barrel 20 is a direction that is perpendicular or approximately perpendicular to optical axis Ax (x-axis).

[0033] The through hole 60 is composed of a first hole portion 61, a recessed portion 62, and a second hole portion 63. The first hole portion 61 is formed on the outer peripheral wall surface 201 side of the lens barrel 20. The recessed portion 62 is formed on the second region 204 side. The recessed portion 62 may be a hole formed in the inner peripheral wall surface 202, or may be a groove extending in the circumferential direction. The second hole portion 63 connects the first hole portion 61 and the recessed portion 62.

[0034] The first hole portion 61 is formed in a tapered shape such that the diameter decreases as it approaches the second region 204 from the outer peripheral wall surface 201. The length of the recess 62 in the x-axis direction, i.e., the length along the optical axis Ax, and the diameter of the second hole portion 63 are different from each other. Specifically, the length of the recess 62 in the x-axis direction is greater than the diameter of the second hole portion 63. The radial length of the recess 62 is greater than the length of a burr protruding from the end of the second hole portion 63 toward the optical axis Ax. Therefore, a burr generated at the end of the second hole portion 63 is contained inside the recess 62. Note that the burr was generated when the through-hole 60 was drilled during the manufacturing process of the lens barrel 20.

[0035] Furthermore, the length in the x-axis direction of recess 62 is shorter than the length in the x-axis direction of fixing portion 413 (see FIGS. 3A and 3B) of pressing member 40, which will be described later. As a result, the end of through-hole 60 on the optical axis Ax side is shielded by fixing portion 413. Therefore, external light is prevented from entering the interior of barrel 20 via through-hole 60. As a result, it is no longer necessary to place a member for shielding through-hole 60 from light or to inject a light-shielding adhesive into through-hole 60.

[0036] <Through hole 70> As described above, the through hole 70 is formed at a position in the x-axis direction that overlaps with the position at which the spacer member 50 is disposed. The through hole 70 is used to accurately incorporate the lenses 306, 307, and 308 into the third housing portion 23 during the manufacturing process of the lens unit 10. Specifically, the spacer member 50 is aligned using a jig or the like inserted into the through hole 70. Thereafter, an adhesive or the like is applied inside the through hole 70, and the spacer member 50 is fixed inside the third housing portion 23.

[0037] A plurality of through holes 70 are formed along the circumferential direction of the lens barrel 20. For example, three through holes 70 are provided at 120° intervals along the circumferential direction of the lens barrel 20. The number of through holes 70 is not limited to three, and may be four or more. The through holes 70 penetrate the outer peripheral wall surface 201 of the lens barrel 20 and the inner peripheral wall surface 205 of the third housing portion 23. In other words, the through holes 70 are formed along the radial direction of the lens barrel 20.

[0038] The through-hole 70 is composed of a first hole portion 71, a recessed portion 72, and a second hole portion 73. The first hole portion 71 is formed on the outer peripheral wall surface 201 side of the lens barrel 20. The recessed portion 72 is formed on the inner peripheral wall surface 205 side. The recessed portion 72 may be a hole formed in the inner peripheral wall surface 205, or may be a groove extending in the circumferential direction. The second hole portion 73 connects the first hole portion 71 and the recessed portion 72.

[0039] The first hole portion 71 is formed in a tapered shape such that the diameter decreases as it approaches the inner peripheral wall surface 205 from the outer peripheral wall surface 201. The length of the recess 72 in the x-axis direction and the diameter of the second hole portion 73 are different from each other. Specifically, the length of the recess 72 in the x-axis direction is greater than the diameter of the second hole portion 73. The radial length of the recess 72 is greater than the length of a burr protruding from the end of the second hole portion 73 toward the optical axis Ax. Therefore, a burr generated at the end of the second hole portion 73 is contained inside the recess 72. The burr was generated when the through-hole 70 was drilled during the manufacturing process of the lens barrel 20.

[0040] Furthermore, the length of recess 72 in the x-axis direction is shorter than the length of spacer member 50 in the x-axis direction. As a result, the end of through-hole 70 on the optical axis Ax side is shielded by spacer member 50. Therefore, external light is prevented from entering the interior of barrel 20 via through-hole 70. As a result, it is no longer necessary to place a member for shielding through-hole 70 from light or to inject a light-shielding adhesive into through-hole 70.

[0041] <Pressing member 40> Fig. 3A is an external perspective view of the pressing member 40. Fig. 3B is a partial cross-sectional view showing an enlarged view of the vicinity of the pressing member 40 in the cross-sectional view shown in Fig. 2. As shown in Figs. 3A and 3B, the pressing member 40 is formed in a hollow cylindrical shape with the optical axis Ax as its central axis.

[0042] The pressing member 40 has a side wall portion 41, a holding portion 42, and a connecting portion 43. The connecting portion 43 is formed on the holding portion 42.

[0043] <Side wall portion 41> The side wall 41 is cylindrical and centered on the optical axis Ax. The outer diameter of the side wall 41 is equal to or approximately equal to the inner diameter of the first housing portion 21. A contact surface 410 that intersects (orthogonal or approximately orthogonal to) the optical axis Ax (x-axis) is formed at the front end (positive x-axis side) of the side wall 41. Specifically, the contact surface 410 is located at the positive x-axis side end of the side wall 41 and is a ring-shaped flat surface centered on the optical axis Ax. When the first lens 302 and the pressing member 40 are housed in the first housing portion 21, the contact surface 410 comes into contact with a part of the rear end of the first lens 302.

[0044] A connecting portion 412, which is a male screw, is formed along the outer peripheral surface 411 on the rear side (x-axis minus side), which is the other end side of the outer peripheral surface 411 of the side wall portion 41. When the pressing member 40 is housed in the first housing portion 21, the connecting portion 412 and the first region 203 of the first housing portion 21 are screw-connected. In this way, the pressing member 40 is attached inside the first housing portion 21.

[0045] A fixing portion 413 is formed on the outer peripheral surface 411 of the side wall portion 41, on the x-axis + side (front side) of the joining portion 412. When the pressing member 40 is accommodated in the first accommodating portion 21, the fixing portion 413 fits into the second region 204 of the first accommodating portion 21. As a result, the pressing member 40 is fixed and accommodated within the first accommodating portion 21.

[0046] <Holding part 42> The holding portion 42 is formed on the radially inner side of the side wall portion 41. The holding portion 42 is cylindrical with the optical axis Ax as its central axis. The holding portion 42 is formed by a front side surface 421, a rear side surface 422, and an inclined surface 423.

[0047] The front side surface 421 is formed at the front end of the holding portion 42. The front side surface 421 intersects (perpendicular or approximately perpendicular to) the optical axis Ax. The front side surface 421 is located rearward of the contact surface 410 formed at the front end of the side wall portion 41.

[0048] The rear surface 422 is formed at the rear end of the holding portion 42. The rear surface 422 intersects (orthogonal or approximately orthogonal to) the optical axis Ax. The rear surface 422 is located forward of the rear end of the side wall portion 41. The distance between the rear surface 422 and the contact surface 410 in the x-axis direction is set to be equal to or approximately equal to the design distance between the first lens 302 and the second lens 303 in the x-axis direction.

[0049] When the pressing member 40 is accommodated in the first accommodation portion 21, the rear side surface 422 comes into contact with the second lens 303 accommodated in the second accommodation portion 22. As a result, the holding portion 42 holds the second lens 303 on the other end side (rear side) of the side wall portion 41 in the direction along the x-axis. In addition, the inner diameter of the rear side surface 422 is smaller than the inner diameter of the front side surface 421.

[0050] The inclined surface 423 connects the front side surface 421 and the rear side surface 422. Because the inner diameter of the rear side surface 422 is smaller than the inner diameter of the front side surface 421, the inner wall surface of the holding portion 42 is formed in a tapered shape in which the inner diameter decreases toward the negative x-axis side. The inclination angle of the inclined surface 423 with respect to the optical axis Ax is set so as to prevent so-called vignetting, which occurs when light passing through the first lens 302 is blocked by the inclined surface 423 and black reflections occur in the corners of the screen.

[0051] <Connection part 43> When the pressing member 40 is accommodated in the first accommodation portion 21, it is screwed to the lens barrel 20 using a jig or the like. The connecting portion 43 is connected to the jig or the like used at this time. A plurality of connecting portions 43 are formed on the surface of the holding portion 42 along the circumferential direction centered on the optical axis Ax. FIG. 3A shows a case where two connecting portions 43 are provided at equal intervals along the circumferential direction. However, the number and positions of the connecting portions 43 are determined according to the shape of the jig. In other words, the number and positions of the connecting portions 43 are not limited to the example shown in FIG. 3A.

[0052] 3B, connecting portion 43 is a recess formed at the boundary between front side surface 421 and inclined surface 423. In other words, front side surface 421 and inclined surface 423 are connecting portion forming surfaces different from contact surface 410.

[0053] As described above, the front side surface 421 is located rearward of the contact surface 410 formed at the front end of the side wall portion 41. The inclined surface 423 is a surface that connects the front side surface 421 and the rear side surface 422. Therefore, when the pressing member 40 is housed in the first housing portion 21, the front side surface 421 and the inclined surface 423, which are the connecting portion forming surfaces, are farther away from the first lens 302 than the contact surface 410.

[0054] The connecting portion 43 may be a through-hole that penetrates the boundary between the front side surface 421 and the inclined surface 423 and the rear side surface 422. The connecting portion 43 may also be a protruding portion that protrudes from the boundary between the front side surface 421 and the inclined surface 423 toward the front side.

[0055] <Assembly of lens unit 10> The assembly of lens unit 10 will be explained separately as assembling first lens group 31 and second lens group 32 into lens barrel 20 and assembling third lens group 33 into lens barrel 20.

[0056] <Assembly of the first lens group 31 and the second lens group 32 into the lens barrel 20> Lenses 303, 304, and 305 of second lens group 32 are arranged along optical axis Ax in second housing portion 22. When second lens group 32 is arranged in lens barrel 20, pressing member 40 is attached to first housing portion 21. In this case, a tool such as a jig is connected to connecting portion 43, and a rotational force about optical axis Ax is applied to the tool.

[0057] When a rotational force is applied to the tool, the holding member 40, which is screw-connected to the first region 203 at the connecting portion 412, moves along the x-axis direction relative to the lens barrel 20. This adjusts the position of the holding member 40 in the x-axis direction. When the holding member 40 is adjusted to the desired position, the rear surface 422 of the holding portion 42 comes into contact with the lens (second lens) 303. Furthermore, the rear side of the second lens 303 comes into partial contact with the front side of the lens 304. The rear side of the lens 304 comes into partial contact with the front side of the lens 305. The rear side of the lens 305 comes into contact with the rear wall surface 220 of the second storage portion 22.

[0058] When the position of the pressing member 40 is adjusted to a desired position in the x-axis direction, the lenses 303, 304, and 305 of the second lens group 32 are pressed and held by the pressing member 40 toward the negative x-axis side.

[0059] Furthermore, the outer diameter of the side wall portion 41 is equal to or approximately equal to the inner diameter of the first housing portion 21. Therefore, when a rotational force is applied to the holding member 40, the holding member 40 moves along the x-axis direction with the fixing portion 413 sliding relative to the second region 204 of the first housing portion 21. As described above, in the through-hole 60, burrs generated during the drilling process of the second hole portion 63 are contained within the recess 62. Therefore, the fixing portion 413 and the second region 204 can be fitted together without interfering with the sliding of the fixing portion 413 relative to the second region 204 due to burrs. As a result, the holding member 40 is prevented from rattling within the first housing portion 21 and being housed in an inclined state. Therefore, the second lens group 32 held by the holding member 40 can be accurately assembled within the lens barrel 20.

[0060] Thereafter, the lenses 301 and 302 of the first lens group 31 are accommodated in the first housing portion 21, and the lens 301 is pressed from the front side by the front pressing ring 34. As the lens 301 is pressed rearward by the front pressing ring 34, the first lens 302, which is in contact with the rear side of the lens 301, comes into contact with the contact surface 410 of the pressing member 40. As described above, the pressing member 40 is accommodated in the first housing portion 21 in a state where tilting is suppressed. Therefore, the first lens 302, which is in contact with the contact surface 410, is positioned in a state where a decrease in positional accuracy is suppressed.

[0061] Furthermore, as described above, the distance between contact surface 410 and rear side surface 422 in the x-axis direction is equal to or approximately equal to the design distance in the x-axis direction between first lens 302 and second lens 303. As a result, first lens 302 and second lens 303 assembled inside barrel 20 are positioned at a desired distance along the x-axis direction. In other words, pressing member 40 functions as a spacer for first lens 302 and second lens 303.

[0062] Connecting portion 43 is provided on a connecting portion forming surface that is different from contact surface 410. Therefore, even if burrs are generated during processing of connecting portion 43 or during connection between a tool and connecting portion 43, no burrs are generated on contact surface 410 that comes into contact with first lens 302. Therefore, first lens 302 is prevented from tilting or shifting from a desired position due to the influence of burrs. As a result, a decrease in the positional accuracy of first lens 302 within first housing portion 21 is prevented.

[0063] Furthermore, front side surface 421 and inclined surface 423, which are the connecting portion forming surfaces, are provided at positions farther away from first lens 302 than contact surface 410. Therefore, even if a burr falls off during adjustment, the fallen burr is prevented from adhering to contact surface 410. As a result, a decrease in the positional accuracy of first lens 302 within first housing portion 21 is prevented.

[0064] When the first lens group 31, the second lens group 32, and the retaining member 40 are assembled inside the lens barrel 20, an adhesive or the like is applied to the inside of the through-hole 60. As a result, the first lens group 31, the second lens group 32, and the retaining member 40 are housed and fixed inside the lens barrel 20.

[0065] <Assembly of the third lens group 33 into the lens barrel 20> Lenses 306, 307, and 308 of the third lens group 33 and spacer members 50 and 51 are arranged along the optical axis Ax in the third housing section 23. When the third lens group 33 and spacer members 50 and 51 are arranged in the lens barrel 20, a rear pressing ring 35 is attached to the rear side of the lens 308.

[0066] At this time, the position of the spacer member 50 in the x-axis direction, the inclination with respect to the optical axis Ax, etc. are adjusted using a jig or the like inserted into the through-hole 70. As a result, the lenses 306, 307, 308 arranged in the third housing portion 23 can be assembled so that the positions and inclinations thereof are in the desired states.

[0067] As described above, the inner diameter of the third housing portion 23 and the outer diameter of the spacer member 50 are equal or approximately equal. However, the radial length of the recess 72 of the through-hole 70 is greater than the burrs that may occur during the drilling process of the second hole portion 73. This prevents the movement of the spacer member 50 in the x-axis direction from being hindered by burrs during the above adjustment. As a result, the spacer member 50 is prevented from rattle occurring within the third housing portion 23 and being housed in an inclined state. This makes it possible to assemble the third lens group 33 into the lens barrel 20 with high precision.

[0068] When the third lens group 33 and the spacer members 50 and 51 are assembled inside the lens barrel 20, an adhesive or the like is applied to the inside of the through-hole 70. As a result, the third lens group 33 and the spacer members 50 and 51 are housed and fixed inside the lens barrel 20.

[0069] According to the above-described embodiment, at least one of the following advantageous effects can be obtained.

[0070] (1) The lens unit 10 includes a pressing member 40 provided between a first lens 302 and a second lens 303 among the multiple lenses 301 to 308. The pressing member 40 has a sidewall portion 41, a contact surface 410, a holding portion 42, a coupling portion 412, a connecting portion 43, and a front side surface 421 and an inclined surface 423 that form the connecting portion. The contact surface 410 is located at one end (front side) of the sidewall portion 41 in the direction along the optical axis Ax and contacts the first lens 302. The holding portion 42 is provided at the other end (rear side) of the sidewall portion 41 in the direction along the optical axis Ax and contacts the second lens 303 to hold the second lens 303. The coupling portion 412 is provided along the outer periphery of the rear side of the sidewall portion 41 and is threadedly coupled to a first region 203 of an inner circumferential wall surface 202 of the lens barrel 20. A tool for rotating the pressing member 40 around the optical axis Ax is connected to the connecting portion 43. The connecting portion 43 is provided on the front side surface 421 and the inclined surface 423, which are connecting portion forming surfaces different from the contact surface 410.

[0071] This allows the single member, pressing member 40, to function as both a spacer that holds second lens group 32 including second lens 303 and a spacer that positions first lens 302 and second lens 303 at a desired distance. As a result, there is no need to provide a spacer member in addition to pressing member 40, making it possible to reduce the number of parts.

[0072] In this pressing member 40, the contact surface 410 that comes into contact with the first lens 302 and the connecting portion forming surface on which the connecting portion 43 is provided are different surfaces. Therefore, no burrs are generated on the contact surface 410 during adjustment work in which a tool is connected to the connecting portion 43. Even if a burr generated by connecting a tool to the connecting portion 43 falls off, adhesion of the burr to the contact surface 410 is suppressed. This prevents the first lens 302 from tilting or shifting from a desired position. As a result, a decrease in the positional accuracy of the first lens 302 inside the lens barrel 20 is suppressed. In other words, it is possible to position the first lens 302 and the second lens 303 with good positional accuracy in the x-axis direction.

[0073] (2) Front side surface 421 and inclined surface 423, which are the connecting portion forming surfaces, are located at a position farther away from first lens 302 than contact surface 410. This prevents burrs from adhering to contact surface 410, even if they fall off during adjustment. As a result, the positional accuracy of first lens 302 in first housing portion 21 is prevented from decreasing.

[0074] (3) Front side surface 421, which is the connecting portion forming surface, and inclined surface 423 are provided more inward than contact surface 410 in the radial direction intersecting the direction along optical axis Ax. This not only prevents burrs from adhering to contact surface 410 even if they fall off during adjustment, but also increases the contact area between first lens 302 and contact surface 410, thereby preventing first lens 302 from tilting. As a result, it is possible to prevent a decrease in the positional accuracy of first lens 302.

[0075] (4) The connecting portion 43 is a hole provided in the connecting portion forming surface, that is, the front side surface 421 and the inclined surface 423. This makes it possible to connect the holding member 40 to a tool used during adjustment.

[0076] (5) The retaining member 40 is provided with a fixing portion 413 along the outer periphery of the side wall portion 41 at a position on the side wall portion 41 that is different from the joining portion 412 in the direction along the optical axis Ax. The fixing portion 413 fits into a second region 204 that is different from the first region 203 of the inner circumferential wall surface 202 of the lens barrel 20. This prevents the retaining member 40 from rattling within the first housing portion 21 and being housed in an inclined state. Therefore, the second lens group 32 held by the retaining member 40 can be assembled into the lens barrel 20 with high precision. Furthermore, the second lens 303 and the first lens 302 that contacts the contact surface 410 of the retaining member 40 can be positioned at a desired distance along the x-axis direction.

[0077] (6) Lens barrel 20 is provided with through-hole 60 extending in the radial direction. In the direction along optical axis Ax, through-hole 60 is positioned so as to overlap second region 204. As a result, through-hole 60, which is used when adjusting the position of retaining member 40, is shielded from light by fixing portion 413 of retaining member 40. As a result, external light is prevented from entering the interior of lens barrel 20 and adversely affecting the optical characteristics of lens unit 10.

[0078] (7) The through-hole 60 is composed of a first hole 61 provided in the outer peripheral wall surface 201 of the lens barrel 20, a recess 62 provided in the inner peripheral wall surface 202 of the lens barrel 20, and a second hole 63 connecting the first hole 61 and the recess 62. The length of the recess 62 along the optical axis Ax is greater than the diameter of the second hole 63. As a result, burrs that occur in the second hole 63 and extend toward the optical axis Ax are accommodated in the recess 62. This prevents burrs that occur in the through-hole 60 from causing play in the pressing member 40 within the first housing portion 21, preventing the pressing member 40 from being accommodated in an inclined state. As a result, the second lens group 32 held by the pressing member 40 can be accurately assembled within the lens barrel 20. Furthermore, the second lens 303 and the first lens 302 can be positioned at a desired distance along the x-axis direction.

[0079] <First Modification> 3A and 3B. Specifically, the connecting portion 43 of the pressing member 40 does not have to be formed on the radially inner side of the side wall portion 41.

[0080] FIG. 4A is a cross-sectional view of a holding member 40 of a first modified example. As shown in the figure, a connecting portion 43 is provided on a flange 414 formed on an outer peripheral surface 411 of a side wall portion 41. Specifically, the flange 414 is provided on a fixing portion 413 of the side wall portion 41. That is, the connecting portion 43 is formed on the radially outer side of the side wall portion 41. The connecting portion 43 is provided on a front side surface 415 of the flange 414. That is, the front side surface 415 is the connecting portion forming surface. The connecting portion 43 may be a through hole, a recess, or a protrusion, as in the embodiment. The other structures of the holding member 40 are the same as in the embodiment.

[0081] 4B is a cross-sectional view of another example of pressing member 40 of the first modified example. As shown in FIG. 4B, connecting portion 43 is provided radially outward of side wall portion 41 and on the +x-axis side of contact surface 410. Specifically, flange 414 connects to connecting portion 44 formed on outer peripheral surface 411 of side wall portion 41. Connecting portion 44 has an inner diameter larger than the outer diameter of contact surface 410 and is cylindrical with a wall surface extending from the end of outer peripheral surface 411 on the +x-axis side along the x-axis direction toward the +x-axis side.

[0082] The flange 414 is connected to the end of the connecting portion 44 on the +x-axis side. The inner diameter of the flange 414 is larger than the outer diameter of the contact surface 410. In this case, the connecting portion 43 is also provided on the front side surface 415 of the flange 414. In other words, the front side surface 415 is the connecting portion forming surface. The connecting portion 43 may be a through hole, a recess, or a protrusion, as in the embodiment. The other structures of the pressing member 40 are the same as in the embodiment.

[0083] 4B, the case has been described in which the front side surface 415 of the flange 414 is provided closer to the positive x-axis side than the contact surface 410. However, the front side surface 415 and the contact surface 410 may be formed at the same or approximately the same position in the x-axis direction.

[0084] With the above configuration, the position of pressing member 40 along the x-axis can be adjusted by connecting portion 412 of side wall portion 41. Then, fixing portion 413 of side wall portion 41 fits into second region 204 of first housing portion 21, whereby pressing member 40 is fixed and housed within first housing portion 21. As a result, the first modified example can also achieve the same effects as the effects (1), and (4) to (7) obtained by the embodiment. <Second Modification> FIG. 5 is an external perspective view of lens unit 10 of the second modified example. No through-hole 60 is formed in barrel 20 of lens unit 10 of the second modified example. Even in this case, the position along the x-axis can be adjusted by rotating retainer member 40 about optical axis Ax. Then, retainer member 40 is fixed and accommodated in first accommodation portion 21 by fitting fixing portion 413 into second region 204 of first accommodation portion 21. As a result, lens unit 10 of the second modified example can also obtain the same effects as the effects (1) to (5) obtained by the embodiment.

[0085] In the second modified example, a through hole 70 similar to that in the embodiment is formed. Therefore, as in the embodiment, rattle occurs in the spacer member 50 inside the third housing portion 23, and the spacer member 50 is prevented from being housed in an inclined state. Therefore, it is possible to assemble the third lens group 33 inside the lens barrel 20 with high precision.

[0086] Furthermore, the length of recess 72 along optical axis Ax is shorter than the length of spacer member 50 in the x-axis direction. As a result, the end of through-hole 70 on the optical axis Ax side is shielded by spacer member 50. Therefore, external light is prevented from entering the interior of lens barrel 20 via through-hole 70, and adverse effects on the optical characteristics of lens unit 10 are prevented.

[0087] The lens unit 10 of the second modified example may include the pressing member 40 of the first modified example.

[0088] Although various embodiments and modifications have been described above, the present invention is not limited to these. Other embodiments that are conceivable within the scope of the technical idea of ​​the present invention are also included within the scope of the present invention.

[0089] The present technology can be configured as follows.

[0090] (1) A lens unit includes a plurality of lenses including a first lens and a second lens, a lens barrel that houses the plurality of lenses, and a pressing member that is provided between the first lens and the second lens. The pressing member has a cylindrical side wall portion centered on the optical axis of the plurality of lenses, a contact surface that is located at an end of one end of the side wall portion in a direction along the optical axis and that contacts the first lens, a holding portion that is provided at the other end of the side wall portion in a direction along the optical axis and that contacts the second lens to hold the second lens, a connecting portion that is provided along the outer periphery of the other end of the side wall portion and that threadably connects with a first region of the inner wall surface of the lens barrel, and a connecting portion forming surface different from the contact surface that is provided with a connecting portion to which a tool that rotates the pressing member around the optical axis is connected.

[0091] (2) The lens unit according to (1), wherein the connection portion forming surface is provided at a position farther away from the first lens than the contact surface.

[0092] (3) The lens unit according to (1) or (2), wherein the connecting portion forming surface is provided on the inside of the contact surface in a radial direction intersecting with a direction along the optical axis.

[0093] (4) The lens unit according to any one of (1) to (3), wherein the connecting portion is a hole provided in the connecting portion forming surface.

[0094] (5) A lens unit described in any one of (1) to (4), wherein the pressing member has a fixing portion provided along the outer periphery of the side wall portion at a position different from the connecting portion in the direction along the optical axis of the side wall portion, and the fixing portion engages with a second region different from the first region of the inner wall surface of the lens barrel.

[0095] (6) A lens unit as described in (5), wherein the lens barrel has a through hole along the radial direction, the through hole having a first hole portion provided on the outer wall surface side of the lens barrel, a recess portion provided on the inner wall surface side of the lens barrel, and a second hole portion connecting the first hole portion and the recess portion, and the length of the recess portion in the direction along the optical axis is greater than the diameter of the second hole portion.

[0096] (7) The lens unit according to (6), wherein the through hole is positioned so as to overlap with the second region in a direction along the optical axis. [Explanation of symbols]

[0097] 10 lens unit, 20 lens barrel, 30 optical member, 40 pressing member, 41 side wall portion, 42 holding portion, 43 connecting portion, 60, 70 through hole, 61, 71 first hole portion, 62, 72 recessed portion, 63, 73 second hole portion, 201 outer peripheral wall surface, 202 inner peripheral wall surface, 203 first region, 204 second region, 301, 302, 303, 304, 305, 306, 307, 308 lens, 302 first lens, 303 second lens, 410 contact surface, 411 outer peripheral surface, 412 connecting portion, 413 fixing portion, 415, 421 front surface, 422 rear surface, 423 inclined surface, Ax optical axis

Claims

1. a plurality of lenses including a first lens and a second lens; a lens barrel that houses a plurality of the lenses; a pressing member provided between the first lens and the second lens, The pressing member is a cylindrical sidewall portion centered on the optical axes of the plurality of lenses; a contact surface located at an end portion on one end side of the side wall portion in a direction along the optical axis and in contact with the first lens; a holding portion provided on the other end side of the side wall portion in the direction along the optical axis, the holding portion coming into contact with the second lens to hold the second lens; a coupling portion provided along an outer periphery of the other end of the side wall portion and threadably coupled to a first region of an inner periphery of the barrel; a connecting portion forming surface, different from the contact surface, on which a connecting portion is provided to which a tool for rotating the pressing member around the optical axis is connected.

2. 2. The lens unit according to claim 1, The lens unit, wherein the connection portion forming surface is provided at a position farther away from the first lens than the contact surface.

3. 3. The lens unit according to claim 2, The lens unit, wherein the connection portion forming surface is provided more inward than the contact surface in a radial direction intersecting with a direction along the optical axis.

4. The lens unit according to claim 3, The lens unit, wherein the connecting portion is a hole provided in the connecting portion forming surface.

5. 5. The lens unit according to claim 4, the pressing member is provided with a fixing portion along an outer periphery of the side wall portion at a position different from the joining portion in the direction along the optical axis of the side wall portion, The fixing portion is fitted into a second region of the inner peripheral wall surface of the lens barrel, the second region being different from the first region.

6. The lens unit according to claim 5 , The lens barrel is provided with a through hole along the radial direction, the through hole has a first hole portion provided on an outer peripheral wall surface side of the lens barrel, a recessed portion provided on the inner peripheral wall surface side of the lens barrel, and a second hole portion connecting the first hole portion and the recessed portion, A lens unit, wherein the length of the recess in the direction along the optical axis is greater than the diameter of the second hole.

7. 7. The lens unit according to claim 6, A lens unit, wherein the position of the through hole overlaps with the second region in a direction along the optical axis.

Images