Lens unit

Abstract

To provide a lens unit that, when performing eccentricity adjustment of a plastic lens, can reduce positional deviation from an adjustment position.SOLUTION: A lens unit fixes and holds a lens made of plastic that has been moved and adjusted in parallel with a receiving surface for positioning the lens in an optical axis direction, and the lens unit comprises: a lens holder that has the receiving surface and holds the lens; a press-hold member that is fixed with respect to the lens holder; and an elastic member that is arranged between the press-hold member and the lens and presses the lens against the lens holder. The press-hold member has an opening into which a tool is inserted which is for pressing an outer peripheral surface of the lens to move and adjust the lens in parallel with the receiving surface. A position of the lens is fixed by the press-hold member and the elastic member.SELECTED DRAWING: Figure 3

Description

Technical Field

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

Background Art

[0002] In recent years, there has been a demand for higher pixel counts and smaller sizes of surveillance cameras, and eccentricity adjustment for adjusting the optical axis of a lens may be performed. In addition, a plastic lens may be used for the lens.

[0003] [[ID=1S]] As a technique for eccentrically adjusting and holding a lens, the technique of Patent Document 1 is disclosed. Patent Document 1 provides a configuration in which holding claws are provided on a lens holding member, and the lens is sandwiched between a receiving surface and the holding claws to be in a temporarily fixed state. Then, the side surface of the lens is pressed by an adjustment pin through a through hole to perform eccentricity adjustment, and an adhesive is injected through an opening to fix the lens.

Prior Art Documents

Patent Documents

[0004] [[ID=Z7]]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The technique of Patent Document 1 has a configuration in which the lens is adhesively fixed after eccentric adjustment. However, some plastic lenses have low hydrophilicity, and the adhesive strength may be poor in adhesive fixing. In such a case, adhesive peeling may occur in a high-temperature / low-temperature environment or the like, and there is a risk that the lens may shift from the eccentric adjustment position. Further, if the biasing by the holding claws is strengthened to eliminate adhesive fixing, the sliding load on the plastic lens during eccentric adjustment increases, making fine position adjustment difficult.

[0006] The present invention provides a lens unit capable of reducing the displacement of the lens from the adjustment position in a configuration for eccentrically adjusting a plastic lens. [Means for solving the problem]

[0007] To solve the above problems, the lens unit of the present invention is a lens unit that fixes and holds a lens made of plastic after it has been moved and adjusted parallel to a receiving surface that positions the lens in the optical axis direction, and comprises a lens holder having the receiving surface and holding the lens, a pressing member fixed to the lens holder, and an elastic member disposed between the pressing member and the lens and pressing the lens against the lens holder, wherein the pressing member has an opening through which a tool for pressing the outer circumferential surface of the lens and adjusting the lens to move parallel to the receiving surface is inserted, and the position of the lens is fixed by the pressing member and the elastic member. [Effects of the Invention]

[0008] According to the present invention, in a configuration for adjusting the eccentricity of a plastic lens, it is possible to provide a lens unit that can reduce the misalignment of the lens from the adjustment position. [Brief explanation of the drawing]

[0009] [Figure 1] Perspective view of the imaging device 100 of Embodiment 1 [Figure 2] Exploded perspective view of the imaging device 100 of Embodiment 1 [Figure 3] Exploded perspective view of the lens unit 20 of Embodiment 1 [Figure 4] Side cross-sectional view of the lens unit 20 of Embodiment 1 [Figure 5] Perspective view of the lens unit 20 of Embodiment 1 before eccentricity adjustment. [Figure 6] Perspective view of the lens unit 20 of Embodiment 1 after eccentricity adjustment. [Figure 7] Side cross-sectional view of the lens unit 20 of Embodiment 1 after eccentricity adjustment. [Figure 8] Perspective view of the lens unit 20 of Embodiment 2 [Figure 9]Perspective view of the lens unit 20 of Embodiment 3 [Figure 10] Side cross-sectional view of the lens unit 20 of Embodiment 3 during decentration adjustment [Figure 11] Perspective view of the lens unit 20 of Embodiment 4 before decentration adjustment [Figure 12] Perspective view of the lens unit 20 of Embodiment 4 after decentration adjustment [Figure 13] Exploded perspective view of the lens unit 20 of Embodiment 5 [Figure 14] Side cross-sectional view of the lens unit 20 of Embodiment 5 [Figure 15] Side cross-sectional view of the lens unit 20 of Embodiment 6 [Mode for Carrying Out the Invention]

[0010] Hereinafter, preferred embodiments of the present invention will be described in detail based on the accompanying drawings.

[0011] [Embodiment 1] Hereinafter, the lens unit in Embodiment 1 will be described with reference to FIGS. 1 to 7.

[0012] FIG. 1 is a perspective view of the imaging device 100 of Embodiment 1. FIG. 2 is an exploded perspective view of the imaging device 100 of Embodiment 1.

[0013] The imaging device 100 is composed of an imaging lens unit 200 and an image sensor unit 300.

[0014] The imaging lens unit 200 has a front housing member 50 and a rear housing member 51. The imaging lens unit 200 has an imaging optical system including a first lens group 1, a second lens group 2, and a third lens group 3 in order from the subject side, which is the side opposite to the side where the image sensor unit 300 is arranged.

[0015] The front housing member 50 is arranged on the subject side, and the rear housing member 51 is arranged in the imaging lens unit 200. Also, the front housing member 50 is fixed to the rear housing member 51 with screws or the like.

[0016] The first lens group 1 is fixed to the front housing member 50 by heat crimping or the like. The second lens group 2 is held in the lens holder 24. The lens holder 24 is supported so as to be movable in the optical axis O direction of the imaging optical system by engaging with the guide bar 52. The lens holder 24 is also engaged with the guide bar 53, and its rotation around the guide bar 52 is restricted. The lens holder 24 also holds the 2-group rack 25. The 2-group rack 25 is engaged with the lead screw portion of the 2-group drive unit 56, which includes an actuator such as a stepping motor. When the lead screw portion is rotated by the 2-group drive unit 56, the lens holder 24 moves together with the 2-group rack 25 in the optical axis O direction of the imaging optical system. The lens unit 20 is composed of the lens holder 24, the 2-group rack 25, the second lens group 2, the retaining member 26, and the elastic member 27. Details of the lens unit 200 will be described later.

[0017] The third lens group 3 is held in the third lens group frame 31. The third lens group frame 31 is supported so as to be movable in the optical axis O direction by engaging with the guide bar 54. The third lens group frame 31 is also engaged with the guide bar 55, restricting its rotation around the guide bar 54. The third lens group frame 31 also holds the third group rack 32. The third group rack 32 is engaged with the lead screw portion of the third group drive unit 57, which includes an actuator such as a stepping motor. When the lead screw portion is rotated by the third group drive unit 57, the third lens group frame 31 moves together with the third group rack 32 in the optical axis O direction of the imaging optical system. Zooming and focusing of the imaging optical system are performed by the movement of the second lens group 2 and the third lens group 3 in the optical axis O direction of the imaging optical system.

[0018] Guide bars 52, 53, 54, and 55 are held between the front housing member 50 and the rear housing member 51. The second group drive unit 56 and the third group drive unit 57 are fixed to the rear housing member 51 with screws or the like.

[0019] The image sensor unit 300 includes an image sensor 301 and an imaging substrate 302. The image sensor 301 is mounted on the imaging substrate 302. The imaging substrate 302 is fixed to the rear housing member 51 with screws or the like. However, the imaging substrate 302 may also be fixed to the rear housing member 51 via other members, and is not limited to this configuration. An image can be acquired when light focused by the imaging lens unit 200 is imaged onto the image sensor 301.

[0020] Figure 3 is an exploded perspective view of the lens unit 20 of Embodiment 1. Figure 4 is a side cross-sectional view of the lens unit 20 of Embodiment 1. The lens unit 20 includes a second lens group 2, a lens holder 24, a second group rack 25, a retaining member 26, and an elastic member 27.

[0021] The second lens group 2 consists of an adjustment lens 21, a lens 22, and a lens 23. Both lenses 22 and 23 are fixed to the lens holder 24 by heat scribing. However, the method of fixing lenses 22 and 23 may also be adhesive fixing or pressure fixing with a pressing member, and is not limited to this configuration.

[0022] The adjustment lens 21 is a plastic lens. The adjustment lens 21 is made by injection molding. The surface of the adjustment lens 21 that abuts against the receiving surface 24d of the lens holder 24 is the first surface 21a. Also, the surface of the adjustment lens 21 on the side opposite to the first surface 21a in the direction of the optical axis O is the second surface 21b. The portion connecting the first surface 21a and the second surface 21b of the adjustment lens 21 is the side surface portion 21c. The side surface portion 21c has a surface that slopes in a direction away from the optical axis O as it goes from the second surface 21b toward the first surface 21a in the direction of the optical axis O. Note that the sloping surface of the side surface portion 21c does not have to be the entire surface of the side surface portion 21c and may be partial. Alternatively, the side surface portion 21c may be parallel to the optical axis O. Also, the adjustment lens 21 may have a protrusion of a gate trace due to injection molding. Also, for the portion of the side surface portion 21c of the adjustment lens 21 that is exposed even when the pressing member 26 is fixed to the lens holder 24, that is, the exposed portion, the light transmittance is set as t1. Also, the transmittance of the optical surface of the adjustment lens 21 is set as t2. In this case, it is preferable that t1 < t2. Note that the optical surface represents the surface through which the light condensed by the imaging lens unit 200 is transmitted when it forms an image on the imaging element 301. Also, for the portion of the side surface portion 21c of the adjustment lens 21 that is exposed even when the pressing member 26 is fixed to the lens holder 24, it may be shaded with black paint or the like. Thereby, it is possible to prevent light unnecessary for imaging, so-called stray light.

[0023] The lens holder 24 is a member that holds the second lens group 2. The lens holder 24 is substantially cylindrical. The lens holder 24 has a receiving surface 24d for positioning the lens. The receiving surface 24d positions the adjustment lens 21 in the optical axis direction.

[0024] The second-group rack 25 transmits the driving force from the second-group driving unit 56 to the second lens group 2. The second-group rack 25 engages with the lead screw portion of the second-group driving unit 56 that includes an actuator such as a stepping motor.

[0025] The retaining member 26 is a member for holding down the elastic member 27 and the adjustment lens 21. The retaining member 26 is in contact with the elastic member 27. The retaining member 26 is annular in shape. The retaining member 26 has three notches 26a that open in a direction perpendicular to the optical axis O. The notches 26a are for inserting a tool to press the outer circumferential surface of the adjustment lens 21 and move the adjustment lens 21 parallel to the receiving surface 24d of the lens holder 24.

[0026] The notches 26a are provided at three locations that divide the peripheral wall of the retaining member 26 into approximately three equal parts in the circumferential direction. The notches 26a are open so as to penetrate in a direction perpendicular to the optical axis O. In other words, the notches 26a penetrate so that the side portion 21c of the adjustment lens 21 is visible when viewed from a direction perpendicular to the optical axis O. Furthermore, the side portion 21c (outer peripheral surface) of the adjustment lens 21 is exposed through the notches 26a even when the retaining member 26 is fixed to the lens holder 24. Note that there are not necessarily three notches 26a; at least one or more notches 26a are sufficient. The retaining member 26 is fixed to the lens holder 24 by a snap-fit ​​(not shown).

[0027] The elastic member 27 is a component used to fix the adjustment lens 21. The elastic member 27 is annular in shape. The elastic member 27 is sandwiched and compressed between the retaining member 26 and the adjustment lens 21.

[0028] Between the retaining member 26 and the lens holder 24 in the optical axis O direction, an elastic member 27 and an adjustment lens 21 are arranged in that order from the retaining member 26 side. By fixing the retaining member 26 to the lens holder 24, the elastic member 27 is sandwiched and compressed between the retaining member 26 and the adjustment lens 21. As the elastic member 27 is compressed, the adjustment lens 21 is biased in the optical axis O direction relative to the lens holder 24 by the elastic member 27 and is held in the lens holder 24. Note that the fixing of the lens holder 24 and the retaining member 26 may be, for example, adhesive fixing or fastening with screws, and is not limited to fixing by snap fit.

[0029] Figure 5 is a perspective view of the lens unit 20 of Embodiment 1 before eccentricity adjustment. Figure 6 is a perspective view of the lens unit 20 of Embodiment 1 after eccentricity adjustment. Figure 7 is a side cross-sectional view of the lens unit 20 of Embodiment 1 after eccentricity adjustment.

[0030] When adjusting the eccentricity of the adjustment lens 21, an adjustment jig 500, such as a pin, is inserted while checking the image and pressed against the side portion 21c of the adjustment lens 21. The adjustment jig 500 may be configured to, for example, adsorb the adjustment lens 21, and there may be one or more adjustment jigs 500. By moving the adjustment jig 500 forward and backward, the adjustment lens 21 is moved relative to the lens holder 24 to a desired position in a direction perpendicular to the optical axis O. At this time, by pressing with the adjustment jig 500 from a direction perpendicular to the side portion 21c, the adjustment lens 21 is biased relative to the lens holder 24 in the direction of the optical axis O. This prevents the adjustment lens 21 from lifting away from the lens holder 24.

[0031] Furthermore, since the adjustment lens 21 is not biased by the elastic member 27 during eccentricity adjustment, eccentricity adjustment can be performed smoothly in a direction perpendicular to the optical axis O. Alternatively, eccentricity adjustment may be performed with the retaining member 26 engaged with the lens holder 24 to a position where the elastic member 27 is not compressed. Or, eccentricity adjustment may be performed with the adjustment lens 21 biased by engaging the retaining member 26 with the lens holder 24 to a position where the elastic member 27 is compressed to a degree that generates only enough sliding resistance to perform eccentricity adjustment smoothly. By performing eccentricity adjustment with the adjustment lens 21 lightly biased by the elastic member 27, it is possible to prevent the adjustment lens 21 from lifting away from the lens holder 24 regardless of the shape of the side portion 21c.

[0032] With the eccentricity adjustment complete, the retaining member 26 is engaged with the lens holder 24. The retaining member 26 and the lens holder 24 engage by snap-fit. At this time, the position of the adjustment lens 21 is restricted by the adjustment jig 500, so the position of the adjustment lens 21 does not deviate from the desired position after eccentricity adjustment. The adjustment jig 500 restricts the position of the adjustment lens 21 until the retaining member 26 is fixed to the lens holder 24. As a result, the adjustment lens 21 is held in the lens holder 24 at the desired position after eccentricity adjustment. After the adjustment lens 21 is held in place, the adjustment jig 500 is removed, completing the eccentricity adjustment and holding of the adjustment lens 21.

[0033] Furthermore, after the adjustment lens 21 has been fixed in place, a light-shielding member or the like may be placed in the opening of the notch 26a to close the opening.

[0034] As described above, by fixing the retaining member 26 to the lens holder 24 after the eccentricity adjustment is complete, the adjustment lens 21 is held in the lens holder 24 while maintaining the desired position after eccentricity adjustment. In other words, since the adjustment lens 21 can be held by mechanical means rather than adhesive after eccentricity adjustment, positional displacement from the adjustment position can be reduced even in high and low temperature environments. Therefore, according to this embodiment, a lens unit can be provided that can reduce positional displacement from the adjustment position when adjusting the eccentricity of a lens.

[0035] Furthermore, since the adjustment lens 21 is held in the lens holder 24 by a biasing force in the direction of the optical axis O, it is not subjected to loads from a direction perpendicular to the optical axis O, and distortion of the optical surface is less likely to occur. In addition, since the elastic member 27 biases the surface of the adjustment lens 21 with a substantially uniform force, stress does not concentrate on the adjustment lens 21. Therefore, even when biased with the force necessary to hold the adjustment lens 21, the stress applied to the adjustment lens 21 is distributed, and distortion of the optical surface can be reduced.

[0036] [Embodiment 2] The lens unit in Embodiment 2 will now be described with reference to Figure 8. In this embodiment, components common to Embodiment 1 are denoted by the same reference numerals as in Embodiment 1. Items common to Embodiment 1 will not be described. In Embodiment 1, the retaining member 26 was provided with a notch 26a, but in Embodiment 2, the retaining member 26 is provided with an opening 26b (through hole).

[0037] Figure 8 is an exploded perspective view of the lens unit 20 of Embodiment 2. The retaining member 26 is a member for holding down the elastic member 27 and the adjustment lens 21. The retaining member 26 is substantially annular in shape. The retaining member 26 has three openings 26b (through holes) that open in a direction perpendicular to the optical axis O. The opening 246 is for inserting a tool to press the outer circumferential surface of the adjustment lens 21 and move the adjustment lens 21 parallel to the receiving surface 24d of the lens holder 24. The openings 26b are provided at three locations that divide the peripheral wall of the retaining member 26 into approximately three equal parts in the circumferential direction. The openings 26b penetrate the side surface of the retaining member 26. The openings 26b open in a direction perpendicular to the optical axis O. In other words, the openings 26b penetrate so that the side surface 21c of the adjustment lens 21 is visible when viewed from a direction perpendicular to the optical axis O. The side portion 21c (outer circumferential surface) of the adjustment lens 21 is exposed through the opening 26b even when the retaining member 26 is fixed to the lens holder 24. Note that there are not necessarily three openings 26b; at least one opening 26b is sufficient.

[0038] Furthermore, the method for adjusting and holding the eccentricity is the same as in Embodiment 1.

[0039] According to this embodiment, the opening can be made smaller than in Embodiment 1, and the reduction in the strength of the retaining member 26 can be suppressed. Furthermore, according to this embodiment, similar to Embodiment 1, a lens unit can be provided that can reduce the positional deviation from the adjustment position when adjusting the eccentricity of the lens.

[0040] [Embodiment 3] The lens unit in Embodiment 3 will now be described with reference to Figures 9 and 10. In this embodiment, components common to Embodiment 1 are denoted by the same reference numerals as in Embodiment 1. Items common to Embodiment 1 will not be described. Embodiment 3 differs in shape from the notch 26a of Embodiment 1 and the opening 26b of Embodiment 2.

[0041] Figure 9 is an exploded perspective view of the lens unit 20 of Embodiment 3. Figure 10 is a side cross-sectional view of the lens unit 20 of Embodiment 3 during eccentricity adjustment.

[0042] Figure 8 is an exploded perspective view of the lens unit 20 of Embodiment 2. The retaining member 26 is a member for holding the elastic member 27 and the adjustment lens 21. The retaining member 26 is substantially cylindrical in shape. The retaining member 26 has three openings 26c (through holes) that are perpendicular to the optical axis O and opening in the direction of the optical axis O. In other words, the openings 26c extend across the side surface of the retaining member 26 and the side surface of the object. Here, the side surface represents the portion of the retaining member 26 that is formed in a substantially cylindrical shape surrounding the optical axis O. The side surface of the object represents the portion that is formed in a substantially annular shape as a plane perpendicular to the direction of the optical axis O. Also, the side surface and the side surface of the object are substantially perpendicular and connected. Note that in Figures 9 and 10, the openings 26c are shown as opening shapes, but they may also be notch shapes that extend to the outer edge on the lens holder 24 side.

[0043] The openings 26c are for inserting a tool to press against the outer surface of the adjustment lens 21 and move the adjustment lens 21 parallel to the receiving surface 24d of the lens holder 24. The openings 26c are provided at three locations that divide the peripheral wall of the retaining member 26 into approximately three equal parts in the circumferential direction. A portion of the adjustment lens 21 is exposed through the openings 26c. The side portion 21c (outer surface) of the adjustment lens 21 is exposed through the openings 26c even when the retaining member 26 is fixed to the lens holder 24. Note that there are not necessarily three openings 26c; at least one or more openings 26c are sufficient.

[0044] The adjustment lens 21 has a connection portion 21d between the side portion 21c and the second surface 21b. The connection portion 21d may be edge-shaped, chamfered, or rounded. Even when the retaining member 26 is fixed to the lens holder 24, at least a portion of the connection portion 21d of the adjustment lens 21 is exposed through the opening 26c of the retaining member 26.

[0045] When performing eccentricity adjustment of the adjustment lens 21, an adjustment jig 500, such as a pin, is inserted into the opening 26c of the retaining member 26 and pressed against the connection portion 21d of the adjustment lens 21. At this time, the adjustment jig 500 presses against the connection portion 21d from a direction toward the lens holder 24, rather than from a direction perpendicular to the optical axis O. As a result, the adjustment lens 21 is biased toward the optical axis O relative to the lens holder 24, and the adjustment lens 21 does not lift away from the lens holder 24. Other eccentricity adjustment and holding methods are the same as in Embodiment 1.

[0046] According to this embodiment, the adjustment lens 21 can be prevented from floating relative to the lens holder 24 without tilting the side surface 21c of the lens with respect to the optical axis O. This suppresses radial expansion of the lens 21 and the lens unit 20. Furthermore, similar to Embodiment 1, a lens unit can be provided that reduces positional deviation from the adjustment position when adjusting the eccentricity of the lens.

[0047] [Embodiment 4] The lens unit in Embodiment 4 will now be described with reference to Figures 11 and 12. In this embodiment, components common to Embodiment 1 are denoted by the same reference numerals as in Embodiment 1. Items common to Embodiments 1 and 2 will not be described. In this embodiment, the size of the opening 26b of the retaining member 26 and the method of fixing the retaining member 26 to the lens holder 24 differ from those of Embodiment 2.

[0048] Figure 11 is a side cross-sectional view of the lens unit 20 of Embodiment 4 during eccentricity adjustment. Figure 12 is a side cross-sectional view of the lens unit 20 of Embodiment 4 after eccentricity adjustment.

[0049] The retaining member 26 has three openings 26d. The openings 26d open in a direction perpendicular to the optical axis O. In Figures 11 and 12, the openings 26d are shown as an opening shape, but they may also be notches that extend to the outer edge on the lens holder 24 side. The openings 26d extend in the direction of the outer circumferential surface of the retaining member 26. Let r be the distance of the openings 26d from the optical axis of the adjustment lens 21, and let θ be the angle at which the retaining member 26 rotates relative to the lens holder 24 in the direction of the optical axis when the retaining member 26 is fixed to the lens holder 24. Let L be the size (arc length) of the openings 26d. In this case, the relationship L > rθ holds.

[0050] The lens holder 24 and the retaining member 26 have threaded portions (not shown). In this embodiment, the lens holder 24 fixes the retaining member 26 to the lens holder 24 by engaging the threaded portion of the retaining member 26 with the threaded portion of the lens holder 24.

[0051] The method for adjusting and holding the eccentricity of the adjustment lens 21 is described below. First, the retaining member 26 is temporarily fixed to the lens holder 24 by screw engagement to a position where the biasing member 27 is not compressed, or where the biasing member 27 is compressed to the extent that only sliding resistance is generated that allows for sufficiently smooth eccentricity adjustment. Next, at least one adjustment jig 500, such as a pin, is inserted into the opening 26d of the retaining member 26. Furthermore, the adjustment jig 500 is used to press or attract the side portion 21c of the adjustment lens 21, and the side portion 21c of the adjustment lens 21 is moved forward and backward to move the adjustment lens 21 to a desired position in a direction perpendicular to the optical axis O relative to the lens holder 24.

[0052] With the eccentricity adjustment complete, the retaining member 26 is rotated to further engage with the lens holder 24 with screws, thereby fixing the lens holder 24 to the retaining member 26.

[0053] Furthermore, if the coefficient of friction between the elastic member 27 and the retaining member 26 is μ1, the coefficient of friction between the elastic member 27 and the adjustment lens 21 is μ2, and the coefficient of friction between the adjustment lens 21 and the lens holder 24 is μ3, then it is preferable that μ1 < μ3 or μ2 < μ3. In this way, even if a load is generated in the rotational direction of the optical axis O when the retaining member 26 is screw-engaged with the lens holder 24, the elastic member 27 can slide and suppress the rotation of the adjustment lens 21.

[0054] Furthermore, if the relationship is μ1 < μ3 or μ2 < μ3, even if the adjustment jig 500 is separated from the adjustment lens after the eccentricity adjustment is complete and the retaining member 26 is screw-engaged to the lens holder 24, it is possible to fix the lens while maintaining its adjusted state. Similar to Embodiment 1, a lens unit can be provided that can reduce positional deviation from the adjustment position when adjusting the eccentricity of a lens.

[0055] [Embodiment 5] The lens unit in Embodiment 5 will now be described with reference to Figures 13 and 14. In this embodiment, components common to Embodiment 1 are denoted by the same reference numerals as in Embodiment 1. Furthermore, the description of components common to Embodiment 1 will be omitted. Furthermore, the description of components common to Embodiment 1 will be omitted. The lens unit 20 of Embodiment 3 has a plate member 28.

[0056] Figure 13 is an exploded perspective view of the lens unit 20 of Embodiment 5. Figure 14 is a side cross-sectional view of the lens unit 20 of Embodiment 5.

[0057] The lens unit 20 includes a second lens group 2, a lens holder 24, a second group rack 25, a retaining member 26, an elastic member 27, and a plate member 28.

[0058] Between the retaining member 26 and the lens holder 24 in the optical axis O direction, an elastic member 27, a plate member 28, and an adjustment lens 21 are arranged in that order from the retaining member 26 side. By fixing the retaining member 26 to the lens holder 24, the elastic member 27 is sandwiched and compressed between the retaining member 26 and the plate member 28. As the elastic member 27 is compressed, the adjustment lens 21 is biased in the optical axis O direction relative to the lens holder 24 by the elastic member 27 together with the plate member 28, and is held in the lens holder 24.

[0059] Furthermore, the eccentricity adjustment and holding method is the same as in Embodiment 1. The coefficient of friction between the elastic member 27 and the retaining member is μ1, the coefficient of friction between the elastic member 27 and the plate member is μ3, the coefficient of friction between the plate member 28 and the adjustment lens is μ4, and the coefficient of friction between the adjustment lens 21 and the lens holder is μ6. In this case, it is preferable that μ1 < μ6, μ3 < μ6, or μ4 < μ6. This allows the elastic member 27 or the plate member 28 to slide and suppress the rotation of the adjustment lens 21 even when a load is generated in the rotational direction of the optical axis O when the retaining member 26 is screwed into the lens holder 24.

[0060] In this embodiment as well, the lens holder 24 may have an opening 24b instead of a notch 24a, similar to Embodiment 2.

[0061] According to this embodiment, similar to Embodiment 1, a lens unit can be provided that can reduce positional deviation from the adjustment position when adjusting the eccentricity of the lens. Furthermore, even if the elastic member 27 is made of a material that does not slide easily, the plate member 28 slides, so the rotation of the adjustment lens 21 can be suppressed.

[0062] [Embodiment 6] The lens unit in Embodiment 6 will now be described with reference to Figure 15. In this embodiment, components common to Embodiment 1 are denoted by the same reference numerals as in Embodiment 1. Components common to Embodiment 1 will not be described. The lens unit 20 of Embodiment 6 has a plate member 28, similar to Embodiment 5, and the plate member 28 also serves as a fixed aperture. The arrangement of the plate member 28 and the elastic member 27 differs from that of Embodiment 5.

[0063] Figure 15 is a side cross-sectional view of the lens unit 20 of Embodiment 6.

[0064] The plate member 28 is a fixed aperture, shielding the adjustment lens 21 from unwanted light rays. The plate member 28 has a light-shielding function. Between the retaining member 26 and the lens holder 24 in the optical axis O direction, the plate member 28, elastic member 27, and adjustment lens 21 are arranged in order from the retaining member 26 side. By screwing the retaining member 26 into the lens holder 24 and fixing it, the elastic member 27 is sandwiched and compressed between the plate member 28 and the adjustment lens 21. As the elastic member 27 is compressed, the adjustment lens 21 is biased in the optical axis O direction relative to the lens holder 24 by the elastic member 27 and is held in the lens holder 24.

[0065] Furthermore, the eccentricity adjustment and holding method is the same as in Embodiment 1. The coefficient of friction between the elastic member 27 and the adjustment lens is μ2, the coefficient of friction between the elastic member 27 and the plate member is μ3, the coefficient of friction between the plate member 28 and the retaining member is μ5, and the coefficient of friction between the adjustment lens 21 and the lens holder is μ6. In this case, it is preferable that μ2 < μ6, μ3 < μ6, or μ5 < μ6. This allows the elastic member 27 or the plate member 28 to slide and suppress the rotation of the adjustment lens 21 even when a load is generated in the rotational direction of the optical axis O when the retaining member 26 is screwed into the lens holder 24.

[0066] In this embodiment as well, the retaining member 26 may have an opening 26b instead of a notch 26a, similar to Embodiment 2.

[0067] According to this embodiment, similar to Embodiment 1, a lens unit can be provided that can reduce positional deviation from the adjustment position when adjusting the eccentricity of the lens. Also, similar to Embodiment 3, rotation of the adjustment lens 21 can be suppressed. Furthermore, since the plate member 28 also serves as a fixed aperture, the number of parts can be reduced.

[0068] Although preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of its gist. Furthermore, the invention is not limited to any configuration that takes design functionality into consideration. [Explanation of Symbols]

[0069] 1. First lens group 2. Second lens group 3. Third lens group 21 Adjustable lenses 21a Lens first surface 21b Lens second surface 21c Lens side 21d Connection part 22, 23 lenses 24 Lens holder 25 racks, 2 groups 26 Retaining member 26a Notch 26b, 26c, 26d opening 27 Elastic members 28 Plate members 31 Third lens group frame 32 racks with 3 groups 50 Front housing member 51 Rear housing member 52, 53, 54, 55 Guide bars 56 Group 2 drive unit 57 3-group drive unit 200 imaging lens unit 300 Image Sensor Unit 301 Image sensor 302 Imaging substrate

Claims

1. A lens unit that fixes and holds a lens made of plastic after it has been moved and adjusted parallel to a receiving surface that positions the lens in the optical axis direction, A lens holder having the aforementioned receiving surface and holding the lens, A retaining member fixed to the lens holder, The system includes an elastic member positioned between the retaining member and the lens, which presses the lens against the lens holder, The retaining member has an opening through which a tool is inserted for pressing the outer surface of the lens and adjusting the lens to move parallel to the receiving surface. The lens unit is characterized in that the position of the lens is fixed by the retaining member and the elastic member.

2. The lens unit according to claim 1, characterized in that the opening is a through hole or a notch.

3. The lens unit according to claim 1, characterized in that the opening is provided on the side surface of the retaining member.

4. The lens unit according to claim 1, characterized in that the opening is provided on a surface perpendicular to the side surface of the retaining member.

5. The lens unit according to claim 1, characterized in that the retaining member is fixed to the lens holder by a snap fit.

6. The lens unit according to claim 1, characterized in that the retaining member is fixed to the lens holder by screwing it into the lens holder.

7. The lens unit according to claim 1, characterized in that the outer surface of the lens is inclined to move away from the optical axis of the lens as it approaches the surface of the lens that contacts the lens holder.

8. It further comprises a plate member, The lens unit according to claim 1, characterized in that the plate member is disposed between the lens and the elastic member.

9. It further comprises a plate member, The lens unit according to claim 1, characterized in that the plate member is disposed between the pressing member and the elastic member.

10. The lens unit according to claim 9, characterized in that the plate member is a fixed aperture.

Images