Lens tilt adjustment mechanism and lens barrel

Abstract

To provide a lens tilt adjustment mechanism that has a relatively simple configuration, has a small number of components, has reduced assembly man-hours, has reduced man-hours during tilt adjustment, and can accurately perform tilt adjustment.SOLUTION: A tilt adjustment mechanism adjusts the direction of an optical axis of a lens with respect to a reference optical axis of a lens barrel. The tilt adjustment mechanism comprises: a lens holding frame that holds the lens; an adjustment member that can advance or retreat in a direction substantially perpendicular to the reference optical axis; a base lens frame that can provide the adjustment member so that it can advance or retreat in the direction substantially perpendicular to the reference optical axis; and an urging member that urges the lens holding frame in the direction of the reference optical axis to press the lens holding frame to be fixed to the adjustment member. In a contact part of the adjustment member and the lens holding frame, any one of the adjustment member and the lens holding frame has at least an inclined part that is inclined with respect to a surface perpendicular to the reference optical axis.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a tilt adjustment mechanism for a lens and a lens barrel provided with the tilt adjustment mechanism for the lens.

Background Art

[0002] In optical devices that require high optical performance, it has become extremely difficult to ensure the desired optical performance simply by attaching a lens to a lens barrel. Therefore, a lens barrel is provided with a lens shift adjustment mechanism (adjustment for aligning the position of the optical center of the lens with the reference optical axis of the lens barrel) and a lens tilt adjustment mechanism (adjustment for aligning the direction of the optical axis of the lens with the reference optical axis of the lens barrel), and optical adjustment (shift adjustment and tilt adjustment) is performed to ensure the desired optical performance when attaching the lens to the lens barrel.

[0003] Here, regarding the tilt adjustment mechanism, in Patent Document 1, a tilt adjustment mechanism is proposed in which one or more adjustment members (washers) are inserted between a lens chamber that fixes a lens and a lens barrel frame that fixes the lens chamber, so that the optical axis of the lens fixed to the lens chamber coincides with the optical axis of the lens barrel frame. However, in the tilt adjustment mechanism that inserts an adjustment member, in order to insert the adjustment member, it is necessary to remove the lens chamber from the lens barrel frame, and there is a problem that the number of man-hours is large. Furthermore, since the resolution of tilt adjustment cannot be less than the thickness of the adjustment member, there is also a problem that it is difficult to adjust with high precision. Although it is possible to improve the resolution of tilt adjustment by preparing adjustment members with different thicknesses, there is also a problem that the cost increases when preparing adjustment members with different thicknesses.

[0004] Therefore, as a tilt adjustment mechanism different from the adjustment mechanism that inserts an adjustment member, in Patent Document 2, a lens is pressed in the optical axis direction by a lens retainer against a lens receiving portion at the periphery of the opening of a lens barrel to assemble the lens to the lens barrel, and a lens device is proposed in which the position of the lens is adjusted by biasing the lens in a direction substantially perpendicular to the optical axis by an adjustment screw screwed into the lens barrel.

[0005] Further, in Patent Document 3, there is provided a lens holding frame for holding a lens, a mounting member to which the lens holding frame is attached, and a tilting adjustment member for adjusting the position of the lens holding frame with respect to the mounting member to adjust the tilt of the lens holding frame with respect to the optical axis. An urging spring for pressing the lens holding frame against the tilting adjustment member in the optical axis direction is provided, and a lens barrel in which a support cylinder portion formed at an eccentric position is formed in the tilting adjustment member has been proposed.

[0006] Further, in Patent Document 4, there are provided a lens holding frame, an adjustment frame for holding the lens holding frame so as to be displaceable in the lens tilting direction, a flexible body, a screw, and a piece member. The flexible body and the piece member have a contact portion that can contact each other in the optical axis direction. At least one contact portion of the flexible body and the piece member is formed on an inclined portion where the distance from the axis of the screw decreases as it approaches the optical axis. The adjustment frame and the lens holding frame are provided with engaging means for restricting the relative movement between the adjustment frame and the lens holding frame by engaging in the optical axis direction and being elastically deformable with respect to the movement. A lens tilting adjustment device has been proposed.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0008] However, in the lens device disclosed in Patent Document 2, the lens is tilted by biasing it in a direction substantially perpendicular to the optical axis while the lens is pressed in the optical axis direction by a lens retainer against the lens receiving portion at the periphery of the opening of the lens barrel. Therefore, there is a problem that the lens may be damaged during tilt adjustment. Further, since the lens is pushed in a direction substantially perpendicular to the optical axis, there is also a problem that the position of the optical center of the lens is displaced from the position of the optical axis by tilt adjustment.

[0009] Also, in the lens barrel of Patent Document 3, by adopting a tilting adjustment member formed with a support cylinder portion formed at an eccentric position, when the tilting adjustment member is rotated, the contact position in the optical axis direction between the support cylinder portion formed at the eccentric position of the tilting adjustment member and the acting portion changes, thereby adjusting the tilt of the lens holding frame. Therefore, the tilt amount of the lens holding frame depends on half a rotation of the tilting adjustment member. In this case, there is a problem that the tilt adjustment range of the lens holding frame cannot be made large. Further, since it is adjusted by half a rotation of the tilting adjustment member, there is also a problem that it is difficult to adjust with high precision.

[0010] Also, in the lens tilt adjustment device of Patent Document 4, a screw is advanced and retracted in a direction intersecting the optical axis, and at least one contact portion between a flexible body and a slider formed on an inclined portion where the distance from the axis of the screw decreases as it approaches the optical axis acts on the lens holding frame. Therefore, a member that elastically deforms elastically deforms to adjust the tilt of the lens holding frame. Thus, there is a problem that the number of parts of the lens tilt adjustment device is large and the structure becomes complicated. Further, since the elastic deformation of the member is utilized, there is also a problem that there is a concern that adverse effects such as a change in the mounting state of the lens may occur due to a change in the shape of the member.

[0011] The present invention has been made in view of such circumstances. The present invention has a relatively simple structure, a small number of parts, a small number of assembly man-hours, a small number of man-hours during tilt adjustment, enables tilt adjustment with high precision, and even when tilt adjustment is performed, the shapes of members such as the lens holding frame other than the biasing member do not change. An object of the present invention is to provide a tilt adjustment mechanism for a lens and a lens barrel provided with the tilt adjustment mechanism for the lens.

Means for Solving the Problems

[0012] As a result of intensive research to solve the above-described problems, the inventors have conceived a tilt adjustment mechanism for a lens and a lens barrel provided with the tilt adjustment mechanism for the lens as follows.

[0013] The tilt adjustment mechanism for a lens according to the present invention is a tilt adjustment mechanism for adjusting the orientation of the optical axis of a lens with respect to the reference optical axis of a lens barrel, and includes a lens holding frame that holds the lens, and a reference optical axis of the lens barrel. An adjustment member that can move forward and backward in a direction substantially perpendicular to the axis, a base lens frame that can be provided in a state where the adjustment member can move forward and backward in a direction substantially perpendicular to the reference optical axis of the lens barrel, and the reference optical axis direction of the lens barrel. And a biasing member for pressing and fixing the lens holding frame against the adjustment member. At the contact portion between the adjustment member and the lens holding frame, either the adjustment member or the lens holding frame is perpendicular to the plane perpendicular to the reference optical axis of the lens barrel. A tilt adjustment mechanism for a lens is adopted, which has at least an inclined portion inclined with respect to the surface.

[0014] The lens barrel according to the present invention adopts a lens barrel characterized by including the above-described tilt adjustment mechanism for a lens.

Effects of the Invention

[0015] The tilt adjustment mechanism of the lens according to the present invention has a relatively simple structure, a small number of components, a small number of assembly man-hours, and a small number of man-hours during tilt adjustment. Therefore, the man-hours and costs during manufacturing can be suppressed. And it is possible to perform tilt adjustment with high precision, and since the shapes of members such as the lens holding frame other than the biasing member do not change even when tilt adjustment is performed, a desired optical performance can be ensured, and an optical device having high optical performance can be provided.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0017] Hereinafter, embodiments of a tilt adjustment mechanism of a lens according to the present invention and a lens barrel provided with the tilt adjustment mechanism of the lens will be described. Note that what is described below merely shows one aspect and is not to be construed as being limited to the following description.

[0018] 1. First Embodiment of Tilt Adjustment Mechanism of Lens The tilt adjustment mechanism of the lens according to the present invention is a tilt adjustment mechanism of the lens that adjusts the direction of the optical axis of the lens with respect to the reference optical axis of the lens barrel, and includes a lens holding frame that holds the lens, an adjustment member that can move forward and backward in a direction substantially perpendicular to the reference optical axis of the lens barrel, a base lens frame that can be provided in a state where the adjustment member can move forward and backward in a direction substantially perpendicular to the reference optical axis of the lens barrel, and a biasing member for biasing the lens holding frame against the adjustment member and fixing it. And at the contact portion between the adjustment member and the lens holding frame, at least one of the adjustment member and the lens holding frame has an inclined portion that is inclined with respect to a plane perpendicular to the reference optical axis of the lens barrel.

[0019] In the first embodiment of the tilt adjustment mechanism of the lens, at the contact portion between the adjustment member and the lens holding frame, the adjustment member has at least an inclined portion that is inclined with respect to a plane perpendicular to the reference optical axis of the lens barrel. FIG. 1 shows a perspective view of the intermediate lens barrel 1 with the tilt adjustment mechanism of the lens according to the present invention incorporated therein. FIG. 2 shows an exploded perspective view of FIG. 1 in the first embodiment. FIG. 3 shows FIG. a viewed from the optical axis direction of FIG. 1 and cross-sectional view b taken along line A-A of FIG. a. FIG. 4 shows FIG. a viewed from a direction perpendicular to the optical axis of FIG. 1 and cross-sectional view b taken along line C-C of FIG. 3b. The intermediate lens barrel 1 is a part of the lens barrel for constructing the entire lens barrel, but the intermediate lens barrel 1 may be the entire lens barrel. The reference optical axis of the lens barrel is the optical axis that should be made to coincide when adjusting the direction of the optical axis of the lens using the tilt adjustment mechanism of the lens according to the present invention. For example, it may be the optical axis in the design of the entire lens barrel, or the optical axis of a lens other than the lens whose optical axis is adjusted using the tilt adjustment mechanism of the lens.

[0020] In FIG. 2, the tilt adjustment mechanism of the lens according to the present invention includes a lens holding frame 3a that holds the lens 11, an adjustment member 4a that can move forward and backward in a direction substantially perpendicular to the reference optical axis of the intermediate lens barrel 1, a base lens frame 2 that can be provided in a state where the adjustment member 4a can move forward and backward in a direction substantially perpendicular to the reference optical axis of the intermediate lens barrel 1, and a biasing member 5 for pressing and fixing the lens holding frame 3a against the adjustment member 4a by biasing in the direction of the reference optical axis of the intermediate lens barrel 1. Further, the biasing member 5 is fixed to the base lens frame 2 using biasing member mounting screws 6. Note that the lenses 10 and 11 may be lenses having any surface shape as long as they are lenses, and may be single lenses or cemented lenses. Also, the base lens frame 2 may hold the lens 10 as shown in FIG. 2, or may be hollow without holding the lens 10. Note that the directions of the object side and the eyepiece side in each figure of this specification are not particularly limited. That is, the tilt adjustment mechanism of the lens according to the present invention can be used regardless of which direction is the object side and which direction is the eyepiece side.

[0021] As shown in FIG. 3b, the biasing member 5 is installed at a position where it sandwiches the lens holding frame 3a between itself and the adjustment member 4a. With this structure, the biasing member 5 biases in the direction of the reference optical axis of the intermediate lens barrel 1 so as to press the lens holding frame 3a against the adjustment member 4a. As shown in FIG. 3a, the biasing members 5 are arranged at three positions in the circumferential direction of the base lens frame 2. And, as can be understood from FIGS. 3a, 3b, and 4b, the adjustment members 4a are arranged at three positions in the circumferential direction of the base lens frame 2 at positions where the biasing members 5 exert a biasing force. Note that the arrangement distances of the three adjustment members 4a from the center of the base lens frame 2 may be different distances, but it is preferable that the arrangement distances of the three adjustment members 4a from the center of the base lens frame 2 are the same distance.

[0022] As shown in Fig. 3b, the lens holding frame 3a biased by the biasing member 5 is pressed and fixed in position by contacting the adjusting member 4a provided on the base lens frame 2. Here, it is determined by including three points that are not on the same straight line geometrically. That is, by arranging the three adjusting members 4a in the circumferential direction of the base lens frame 2, the orientation of the lens holding frame 3a contacting the three adjusting members 4a is determined. And thereby, the orientation of the optical axis of the lens 10 held by the lens holding frame 3a is determined.

[0023] Note that although the biasing member 5 shown in Fig. 2 etc. is in the shape of a leaf spring, as long as the biasing force of the biasing member 5 can surely bring the adjusting member 4a and the lens holding frame 3a into contact, any biasing member may be used, for example, a coil spring or an elastic member etc. may be used.

[0024] 〔Adjusting Member〕 Fig. 5 shows an enlarged view of part B of Fig. 3b where the lens holding frame 3a and the adjusting member 4a are in contact. The adjusting member 4a is attached to the base lens frame 2 in a state where it can move forward and backward in a direction substantially perpendicular to the reference optical axis of the lens barrel. The state of being able to move forward and backward is not particularly limited. For example, it may be a structure in which the adjusting member 4a and the base lens frame 2 are screwed together, and the adjusting member 4a can move forward and backward by rotating the adjusting member 4a around a central axis in a direction substantially perpendicular to the reference optical axis of the lens barrel. Also, it may be a structure in which the adjusting member 4a is attached to the base lens frame 2 with an appropriate frictional force, and the adjusting member 4a can move forward and backward by sliding the adjusting member 4a. Furthermore, although not shown in Fig. 5, it may be a structure in which an elastic member is provided in the central direction of the base lens frame 2 of the adjusting member 4a, and the adjusting member 4a is biased from the central side of the base lens frame 2 toward the outer side in a direction substantially perpendicular to the reference optical axis of the lens barrel by the elastic member, so that the adjusting member 4a can move forward and backward. Also, the aforementioned elastic member may be used to improve the axial force of the adjusting member 4a. And the above-described structures of the state of being able to move forward and backward may be combined structures.

[0025] As shown in Fig. 5, the adjustment member 4a has an inclined portion 7 that is inclined with respect to a plane perpendicular to the reference optical axis of the lens barrel in the vicinity of the contact portion between the lens holding frame 3a and the adjustment member 4a. The cross-sectional shape perpendicular to the advancing and retreating direction of the adjustment member 4a including the inclined portion 7 is circular and is line-symmetric with respect to the central axis in the advancing and retreating direction of the adjustment member 4a. That is, the inclination of the inclined portion 7 of the adjustment member 4a is provided such that the diameter of the cross-sectional shape perpendicular to the advancing and retreating direction of the adjustment member 4a decreases as it goes toward the center of the base lens frame 2. Note that the inclination of the inclined portion 7 of the adjustment member 4a may be provided such that the diameter of the cross-sectional shape perpendicular to the advancing and retreating direction of the adjustment member 4a increases as it goes toward the center of the base lens frame 2.

[0026] 〔Lens holding frame〕 The lens holding frame 3a has a convex portion 8 that contacts the inclined portion 7 of the adjustment member 4a at at least one point in the contact portion with the adjustment member 4a. The shape of the convex portion 8 shown in Fig. 5 is hemispherical, but any shape may be used as long as it can appropriately contact the inclined portion 7 of the adjustment member 4a.

[0027] 〔Tilt adjustment operation〕 The tilt adjustment operation performed using the lens tilt adjustment mechanism according to the present invention will be described. The adjustment member 4a has an inclined portion 7 that is inclined with respect to a plane perpendicular to the reference optical axis of the lens barrel in the vicinity of the contact portion between the lens holding frame 3a and the adjustment member 4a. When the adjustment member 4a is advanced and retracted in a direction substantially perpendicular to the reference optical axis of the lens barrel, a force represented by the resultant vector of the force vector component in the reference optical axis direction of the lens barrel and the force vector component in a direction substantially perpendicular to the reference optical axis of the lens barrel is applied to the convex portion 8 of the lens holding frame 3a that is biased by the biasing member 5 and pressed and fixed to the adjustment member 4a. At this time, due to the force vector component in the reference optical axis direction of the lens barrel, the portion of the lens holding frame 3a provided with the convex portion 8 moves in the reference optical axis direction of the lens barrel against the biasing force of the biasing member 5. That is, when one of the three adjustment members 4a is advanced and retracted, the inclined portion 7 of the advanced and retracted adjustment member 4a moves the contacting convex portion 8 in the reference optical axis direction of the lens barrel against the biasing force of the biasing member 5, and thereby, the portion of the lens holding frame 3a provided with the convex portion 8 moves in the reference optical axis direction of the lens barrel. In this way, the orientation of the lens holding frame 3a in contact with the three adjustment members 4a is determined, and thereby, the orientation of the optical axis of the lens 11 held by the lens holding frame 3a is determined.

[0028] As described above, the amount of movement of the convex portion 8 in the reference optical axis direction of the lens barrel is determined by the amount of advancement and retraction of the adjustment member 4a in a direction substantially perpendicular to the reference optical axis of the lens barrel. From this, the inclination angle of the inclined portion 7 with respect to the plane perpendicular to the reference optical axis of the lens barrel is preferably an angle that can ensure the adjustment range required for tilt adjustment, although it also depends on the length of the inclined portion 7 in a direction substantially perpendicular to the reference optical axis of the lens barrel. And although the inclination angle of the inclined portion 7 may not be a constant angle, since tilt adjustment is easy when the movement of the convex portion 8 in the reference optical axis direction of the lens barrel changes linearly according to the amount of advancement and retraction of the adjustment member 4a in a direction substantially perpendicular to the reference optical axis of the lens barrel, the inclination angle of the inclined portion 7 is preferably a constant angle.

[0029] Here, since the amount of movement of the convex portion 8 in the reference optical axis direction of the lens barrel is determined by the amount of advance and retreat of the adjustment member 4a in a direction substantially perpendicular to the reference optical axis of the lens barrel of the adjustment member 4a, for example, in the case of a structure in which the adjustment member 4a is advanced and retreated by rotation of the adjustment member 4a, the amount of movement of the convex portion 8 in the reference optical axis direction of the lens barrel with respect to the amount of rotation of the adjustment member 4a can be reduced, so that tilt adjustment can be performed with high precision.

[0030] In addition, the movement of the lens holding frame 3a due to the force vector component in the direction substantially perpendicular to the reference optical axis of the lens barrel applied to the lens holding frame 3a when the adjustment member 4a moves forward and backward is restricted by the fitting diameter of the lens holding frame 3a to the base lens frame 2 as shown in the lower diagram of FIG. 3b. That is, the lens holding frame 3a does not move in a direction substantially perpendicular to the reference optical axis of the lens barrel even when the adjustment member 4a is advanced and retreated. Further, the movement of the lens holding frame 3a due to the force vector component in the direction substantially perpendicular to the reference optical axis of the lens barrel applied to the lens holding frame 3a when the adjustment member 4a moves forward and backward is not limited to that by the fitting diameter of the lens holding frame 3a to the base lens frame 2, and may be restricted using a positioning boss or the like.

[0031] Even when the tilt adjustment mechanism of the lens according to the present invention is housed in the intermediate lens barrel 1, as shown in FIG. 4a, the head of the adjustment member 4a can be accessed from the outside through the hole portion 9, and an adjustment tool can be inserted and adjusted without disassembling, or an adhesive for fixing the adjustment member 4a after completion of tilt adjustment can be made to flow in. It is preferable to adhesively fix the adjustment member 4a after completion of tilt adjustment so that the adjustment member 4a does not move forward and backward due to vibrations or the like during use of the optical apparatus employing the tilt adjustment mechanism of the lens according to the present invention.

[0032] As described above, the first embodiment of the tilt adjustment mechanism of the lens has a relatively simple structure, a small number of components, a small number of assembly steps, and a small number of steps during tilt adjustment. Therefore, the man-hours and costs during manufacturing can be reduced. And it is possible to perform tilt adjustment with high precision, and even when tilt adjustment is performed, the shapes of members such as the lens holding frame other than the biasing member do not change. Therefore, a desired optical performance can be ensured, and an optical device with high optical performance can be provided.

[0033] 2. Second Embodiment of the Tilt Adjustment Mechanism of the Lens In the second embodiment of the tilt adjustment mechanism of the lens, at the contact portion between the adjustment member and the lens holding frame, the lens holding frame has at least an inclined portion that is inclined with respect to a plane perpendicular to the reference optical axis of the lens barrel. And for the configuration not particularly described hereinafter, it is the same configuration as the first embodiment.

[0034] 〔Adjustment Member〕 FIG. 6 shows a cross-sectional view a taken along line A-A of FIG. 3a in the second embodiment and an enlarged view b of a portion F in FIG. 6a. The adjustment member 4b is attached to the base lens frame 2 in a state where it can move forward and backward in a direction substantially perpendicular to the reference optical axis of the lens barrel. The state of being able to move forward and backward is not particularly limited. For example, it may be a structure in which the adjustment member 4b and the base lens frame 2 are screwed together, and the adjustment member 4b can move forward and backward by rotating the adjustment member 4b around a central axis in a direction substantially perpendicular to the reference optical axis of the lens barrel. Also, it may be a structure in which the adjustment member 4b is attached to the base lens frame 2 with an appropriate frictional force, and the adjustment member 4b can move forward and backward by sliding the adjustment member 4b. Further, as shown in FIG. 7 (corresponding to a 90° lateral view of FIG. 6b), it is a structure in which an elastic member 12 is provided in the central direction of the base lens frame 2 of the adjustment member 4b, and the adjustment member 4b is biased by the elastic member 12 in a direction substantially perpendicular to the reference optical axis of the lens barrel and from the central side of the base lens frame 2 toward the outer side, so that the adjustment member 4b can move forward and backward. Also, the elastic member 12 may be used to improve the axial force of the adjustment member 4b. And the above-described structures of the state of being able to move forward and backward may be combined structures.

[0035] As shown in FIG. 6, the adjustment member 4b has a convex portion 8 that abuts at least at one point against the inclined portion 7 of the lens holding frame 3b in the vicinity of the abutting portion between the lens holding frame 3b and the adjustment member 4b. The cross-sectional shape perpendicular to the advancing and retreating direction of the adjustment member 4b including the convex portion 8 is circular and is line-symmetric with respect to the central axis in the advancing and retreating direction of the adjustment member 4b. The shape of the convex portion 8 shown in FIG. 6 is cylindrical, but any shape may be used as long as it can appropriately abut against the inclined portion 7 of the lens holding frame 3b.

[0036] 〔Lens holding frame〕 The lens holding frame 3b has an inclined portion 7 that abuts at least at one point against the convex portion 8 of the adjustment member 4b at the abutting portion with the adjustment member 4b. The inclined portion 7 of the lens holding frame 3b may have any structure as long as the portion that follows the locus of the abutting portion with the convex portion 8 when the adjustment member 4b is advanced and retreated is the inclined portion according to the present invention. Note that the inclination of the inclined portion 7 of the lens holding frame 3b in FIG. 6b is such that when the adjustment member 4b is advanced toward the center of the lens holding frame 3b and the base lens frame 2, the lens holding frame 3b is pushed out, but it may also be an inclination such that when the adjustment member 4b is advanced outward from the center of the lens holding frame 3b and the base lens frame 2, the lens holding frame 3b is pushed out.

[0037] 〔Tilt adjustment operation〕 The tilt adjustment operation performed using the lens tilt adjustment mechanism according to the present invention will be described. The lens holding frame 3b has an inclined portion 7 that is inclined with respect to a plane perpendicular to the reference optical axis of the lens barrel in the vicinity of the contact portion between the lens holding frame 3b and the adjustment member 4b. When the adjustment member 4b is moved forward and backward in a direction substantially perpendicular to the reference optical axis of the lens barrel, a force represented by the resultant vector of the force vector component in the reference optical axis direction of the lens barrel and the force vector component in a direction substantially perpendicular to the reference optical axis of the lens barrel is applied to the inclined portion 7 of the lens holding frame 3b that is biased by the biasing member 5 and pressed and fixed to the adjustment member 4b. At this time, due to the force vector component in the reference optical axis direction of the lens barrel, the portion of the lens holding frame 3b provided with the inclined portion 7 moves in the reference optical axis direction of the lens barrel against the biasing force of the biasing member 5. That is, when one of the three adjustment members 4b is moved forward and backward, the convex portion 8 of the moved adjustment member 4b moves the inclined portion 7 with which it contacts in the reference optical axis direction of the lens barrel against the biasing force of the biasing member 5, and thereby, the portion of the lens holding frame 3b provided with the inclined portion 7 moves in the reference optical axis direction of the lens barrel. In this way, the orientation of the lens holding frame 3b in contact with the three adjustment members 4b is determined, and thereby, the orientation of the optical axis of the lens 11 held by the lens holding frame 3b is determined.

[0038] As described above, the amount of movement of the inclined portion 7 in the reference optical axis direction of the lens barrel is determined by the amount of forward and backward movement of the adjustment member 4b in a direction substantially perpendicular to the reference optical axis of the lens barrel. From this, the inclination angle of the inclined portion 7 with respect to the plane perpendicular to the reference optical axis of the lens barrel is preferably an angle that can ensure the adjustment range required for tilt adjustment, although it also depends on the length of the inclined portion 7 in a direction substantially perpendicular to the reference optical axis of the lens barrel. And although the inclination angle of the inclined portion 7 may not be a constant angle, since tilt adjustment is easy when the movement of the inclined portion 7 in the reference optical axis direction of the lens barrel changes linearly according to the amount of forward and backward movement of the adjustment member 4b in a direction substantially perpendicular to the reference optical axis of the lens barrel, the inclination angle of the inclined portion 7 is preferably a constant angle.

[0039] Here, since the amount of movement of the lens barrel of the inclined portion 7 in the direction of the reference optical axis is determined by the amount of advance and retreat in a direction substantially perpendicular to the reference optical axis of the lens barrel of the adjustment member 4b, for example, in the case of a structure in which the adjustment member 4b is advanced and retreated by rotation of the adjustment member 4b, the amount of movement of the inclined portion 7 in the direction of the reference optical axis of the lens barrel with respect to the amount of rotation of the adjustment member 4b can be reduced, so that tilt adjustment can be performed with high precision.

[0040] In addition, the movement of the lens holding frame 3b due to the force vector component in the direction substantially perpendicular to the reference optical axis of the lens barrel applied to the lens holding frame 3b when the adjustment member 4b moves forward and backward is restricted by the fitting diameter of the lens holding frame 3b to the base lens frame 2 as shown in the lower diagram of FIG. 6a. That is, the lens holding frame 3b does not move in a direction substantially perpendicular to the reference optical axis of the lens barrel even when the adjustment member 4b is advanced and retreated. Further, the movement of the lens holding frame 3b due to the force vector component in the direction substantially perpendicular to the reference optical axis of the lens barrel applied to the lens holding frame 3b when the adjustment member 4b moves forward and backward is not limited to that by the fitting diameter of the lens holding frame 3b to the base lens frame 2, and may be restricted using a positioning boss or the like.

[0041] Even when the tilt adjustment mechanism of the lens according to the present invention is housed in the intermediate lens barrel 1, as shown in FIG. 4a, the head of the adjustment member 4b can be accessed from the outside through the hole 9, and an adjustment tool can be inserted and adjusted without disassembling, or an adhesive for fixing the adjustment member 4b after tilt adjustment can be made to flow in. After tilt adjustment is completed, it is preferable to adhesively fix the adjustment member 4b so that the adjustment member 4b does not move forward and backward due to vibrations or the like during use of the optical device employing the tilt adjustment mechanism of the lens according to the present invention.

[0042] As described above, the second embodiment of the tilt adjustment mechanism of the lens has a relatively simple structure, fewer components, less assembly man-hours, and less man-hours during tilt adjustment. Therefore, the man-hours and costs during manufacturing can be reduced. And it is possible to perform tilt adjustment with high precision, and since the shapes of members such as the lens holding frame other than the biasing member do not change even when tilt adjustment is performed, desired optical performance can be ensured, and an optical device with high optical performance can be provided.

[0043] 3. Third Embodiment of the Tilt Adjustment Mechanism of the Lens In the third embodiment of the tilt adjustment mechanism of the lens, at the contact portion between the adjustment member and the lens holding frame, the adjustment member has at least an inclined portion that is inclined with respect to a plane perpendicular to the reference optical axis of the lens barrel. Further, it has a flat portion between the inclined portions. And for the configuration not particularly described hereinafter, it is the same configuration as the first embodiment.

[0044] 〔Adjustment Member〕 Fig. 8 shows an enlarged view (90° horizontal) corresponding to part B of Fig. 3b where the lens holding frame 3a and the adjustment member 4c are in contact. The adjustment member 4c is attached to the base lens frame 2 in a state where it can move forward and backward in a direction substantially perpendicular to the reference optical axis of the lens barrel. The state of being able to move forward and backward is not particularly limited. For example, it may be a structure in which the adjustment member 4c and the base lens frame 2 are screwed together, and the adjustment member 4c can move forward and backward by rotating the adjustment member 4c around a central axis in a direction substantially perpendicular to the reference optical axis of the lens barrel. Also, it may be a structure in which the adjustment member 4c is attached to the base lens frame 2 with an appropriate frictional force, and the adjustment member 4c can move forward and backward by sliding the adjustment member 4c. Further, although not shown in Fig. 8, it may be a structure in which an elastic member is provided in the central direction of the base lens frame 2 of the adjustment member 4c, and the adjustment member 4c is urged in a direction substantially perpendicular to the reference optical axis of the lens barrel and from the central side of the base lens frame 2 toward the outer side by the elastic member, so that the adjustment member 4c can move forward and backward. Also, the above-mentioned elastic member may be used to improve the axial force of the adjustment member 4c. And the above-described structures of the state of being able to move forward and backward may be combined structures.

[0045] As shown in FIG. 8, the adjustment member 4c has at least an inclined portion 7 that is inclined with respect to a plane perpendicular to the reference optical axis of the lens barrel in the vicinity of the contact portion between the lens holding frame 3a and the adjustment member 4c. At this time, the adjustment member 4c has a flat portion 13 substantially parallel to a plane perpendicular to the reference optical axis of the lens barrel between the inclined portions 7 in a portion following the locus of the contact portion with the convex portion 8 when the adjustment member 4c is advanced and retracted. The cross-sectional shape perpendicular to the advancing and retracting direction of the adjustment member 4c including the inclined portion 7 and the flat portion 13 is circular and is line-symmetric with respect to the central axis in the advancing and retracting direction of the adjustment member 4c. That is, the inclination of the inclined portion 7 of the adjustment member 4c is provided such that, except for the flat portion 13, the diameter of the cross-sectional shape perpendicular to the advancing and retracting direction of the adjustment member 4c decreases as it goes toward the center of the base lens frame 2. Note that the inclination of the inclined portion 7 of the adjustment member 4c may be provided such that the diameter of the cross-sectional shape perpendicular to the advancing and retracting direction of the adjustment member 4c increases as it goes toward the center of the base lens frame 2.

[0046] 〔Lens holding frame〕 The lens holding frame 3a has a convex portion 8 that contacts at least one point with the inclined portion 7 and the flat portion 13 of the adjustment member 4c at the contact portion with the adjustment member 4c. The shape of the convex portion 8 shown in FIG. 8 is hemispherical, but any shape may be used as long as it can appropriately contact the inclined portion 7 and the flat portion 13 of the adjustment member 4c.

[0047] 〔Tilt adjustment operation〕 A tilt adjustment operation performed using the lens tilt adjustment mechanism according to the present invention will be described. The adjustment member 4c has an inclined portion 7 and a flat portion 13 that are inclined with respect to a plane perpendicular to the reference optical axis of the lens barrel in the vicinity of the contact portion between the lens holding frame 3a and the adjustment member 4c. When the adjustment member 4c is advanced and retracted in a direction substantially perpendicular to the reference optical axis of the lens barrel, a force represented by a resultant vector of a force vector component in the direction of the reference optical axis of the lens barrel and a force vector component in a direction substantially perpendicular to the reference optical axis of the lens barrel is applied to the convex portion 8 of the lens holding frame 3a that is biased by the biasing member 5 and pressed and fixed to the adjustment member 4c. At this time, due to the force vector component in the direction of the reference optical axis of the lens barrel, the portion of the lens holding frame 3a provided with the convex portion 8 moves in the direction of the reference optical axis of the lens barrel against the biasing force of the biasing member 5. That is, when one of the three adjustment members 4c is advanced and retracted, the inclined portion 7 and the flat portion 13 of the advanced and retracted adjustment member 4c move the convex portion 8 in contact therewith in the direction of the reference optical axis of the lens barrel against the biasing force of the biasing member 5, whereby the portion of the lens holding frame 3a provided with the convex portion 8 moves in the direction of the reference optical axis of the lens barrel. In this way, the orientation of the lens holding frame 3a in contact with the three adjustment members 4c is determined, and thereby, the orientation of the optical axis of the lens 11 held by the lens holding frame 3a is determined.

[0048] As described above, the amount of movement of the convex portion 8 in the direction of the reference optical axis of the lens barrel is determined by the amount of advancement and retraction of the adjustment member 4c in a direction substantially perpendicular to the reference optical axis of the lens barrel. From this, the inclination angle of the inclined portion 7 with respect to the plane perpendicular to the reference optical axis of the lens barrel is preferably an angle that can ensure the adjustment range required for tilt adjustment, although it also depends on the length of the inclined portion 7 in a direction substantially perpendicular to the reference optical axis of the lens barrel. And although the inclination angle of the inclined portion 7 may not be a constant angle, since tilt adjustment is easy when the movement of the convex portion 8 in the direction of the reference optical axis of the lens barrel changes linearly according to the amount of advancement and retraction of the adjustment member 4c in a direction substantially perpendicular to the reference optical axis of the lens barrel, the inclination angle of the inclined portion 7 is preferably a constant angle.

[0049] As shown in Fig. 8, the flat portion 13 is provided at a substantially middle portion between the inclined portions 7 in a portion following the locus of the contact portion with the convex portion 8 when the adjustment member 4c is advanced and retracted. When the contact portion with the convex portion 8 is on the flat portion 13, even if the adjustment member 4c is advanced and retracted, the lens holding frame 3a does not move in the direction of the reference optical axis of the lens barrel. Therefore, for example, it can be used for purposes such as clearly defining the adjustment center position at the start of tilt adjustment by positioning the contact portions of all three adjustment members 4c and the convex portion 8 on the flat portion 13 at the time of assembly. From this, it is preferable that the flat portion 13 has a shape that can ensure the length of the above-described locus that can clearly grasp that it is the adjustment center position at the start of tilt adjustment based on the locus of the contact portion with the convex portion 8 when the adjustment member 4c is advanced and retracted in the flat portion 13.

[0050] Here, since the amount of movement of the convex portion 8 in the direction of the reference optical axis of the lens barrel is determined by the amount of advance and retraction of the adjustment member 4c in a direction substantially perpendicular to the reference optical axis of the lens barrel, for example, in the case of a structure in which the adjustment member 4c is advanced and retracted by rotation of the adjustment member 4c, the amount of movement of the convex portion 8 in the direction of the reference optical axis of the lens barrel with respect to the amount of rotation of the adjustment member 4c can be reduced, so that tilt adjustment can be performed with high precision.

[0051] In addition, the movement of the lens holding frame 3a due to the force vector component in a direction substantially perpendicular to the reference optical axis of the lens barrel applied to the lens holding frame 3a when the adjustment member 4c is advanced and retracted is restricted by the fitting diameter of the lens holding frame 3c to the base lens frame 2 as shown in the lower figure of Fig. 3b having the same configuration. That is, the lens holding frame 3a does not move in a direction substantially perpendicular to the reference optical axis of the lens barrel even if the adjustment member 4c is advanced and retracted. Further, the movement of the lens holding frame 3a due to the force vector component in a direction substantially perpendicular to the reference optical axis of the lens barrel applied to the lens holding frame 3a when the adjustment member 4c is advanced and retracted is not limited to that by the fitting diameter of the lens holding frame 3a to the base lens frame 2, and may be restricted using a positioning boss or the like.

[0052] Even when the tilt adjustment mechanism of the lens according to the present invention is housed in the intermediate lens barrel 1, as shown in Fig. 4a, the head of the adjustment member 4c can be accessed from the outside through the hole 9. Without disassembling, an adjustment tool can be inserted for adjustment, or an adhesive for fixing the adjustment member 4c after tilt adjustment can be made to flow in, etc. After the tilt adjustment is completed, it is preferable to adhesively fix the adjustment member 4c so that the adjustment member 4c does not move forward and backward due to vibrations during the use of the optical device employing the tilt adjustment mechanism of the lens according to the present invention.

[0053] This configuration having a flat portion between the inclined portions can also be adopted in the second embodiment of the tilt adjustment mechanism of the lens having at least an inclined portion where the lens holding frame is inclined with respect to a plane perpendicular to the reference optical axis of the lens barrel.

[0054] As described above, the third embodiment of the tilt adjustment mechanism of the lens has a relatively simple structure, a small number of parts, a small number of assembly man-hours, and a small number of man-hours during tilt adjustment. Therefore, the man-hours and costs during manufacturing can be suppressed. And tilt adjustment can be performed with high precision, and even when tilt adjustment is performed, the shapes of members such as the lens holding frame other than the biasing member do not change. Therefore, a desired optical performance can be ensured, and an optical device with high optical performance can be provided.

[0055] 4. Embodiment of the lens barrel The lens barrel according to the present invention includes a tilt adjustment mechanism for a lens, which is any one of a first embodiment of the tilt adjustment mechanism for a lens according to the present invention, a second embodiment of the tilt adjustment mechanism for a lens, and a third embodiment of the tilt adjustment mechanism for a lens. Since the lens barrel according to the present invention is provided with the tilt adjustment mechanism for a lens according to the present invention, the structure is relatively simple, the number of parts is small, the assembly man-hour is small, and the man-hour during tilt adjustment is small, so that the man-hour and cost during manufacturing can be suppressed. And, tilt adjustment can be performed with high precision, and since the shapes of members such as the lens holding frame other than the biasing member do not change even when tilt adjustment is performed, desired optical performance can be ensured and high optical performance can be provided.

[0056] The embodiments according to the present invention described above are one aspect of the present invention and can be appropriately changed without departing from the gist of the present invention. Further, the present invention will be described more specifically with reference to the following examples, but the present invention is not limited to the following examples.

Example

[0057] In Example 1, the tilt adjustment mechanism for a lens of the first embodiment according to the present invention was adopted, and the optical system of Example 1 having the structure shown in FIGS. 2 and 3 was assembled. The lenses 10 and 11 used convex lenses as shown in FIG. 3b. Also, a structure in which the adjustment member 4a and the base lens frame 2 are screwed together was used. The contact position of the convex portion 8 of the lens holding frame 3a during assembly was set to a substantially intermediate position in the inclined portion 7 of the adjustment member 4a.

[0058] Next, when light rays from a point light source were incident on the optical system of Example 1 and the imaging image was confirmed, a deviation of the image of the point light source due to the non-alignment of the optical axis direction of the lens 11 with respect to the optical axis direction of the lens 10 was confirmed. Therefore, while confirming the above-described imaging image, the adjustment member 4a arranged at three positions in the circumferential direction of the base lens frame 2 was rotated and advanced and retracted using a tool, so that the optical axis direction of the lens 11 was aligned with the optical axis direction of the lens 10, which is the reference optical axis. Tilt adjustment was performed. As a result, the deviation of the image of the point light source disappeared in the above-described imaging image.

Example

[0059] In Example 2, the tilt adjustment mechanism of the lens of the second embodiment according to the present invention was adopted, and the optical system of Example 2 having the structure shown in FIG. 6 was assembled. For lenses 10 and 11, convex lenses as shown in FIG. 6a were used. Also, a structure in which the adjustment member 4b and the base lens frame 2 are screwed together was used. When assembling, the contact position of the convex portion 8 of the adjustment member 4b was set to a substantially intermediate position in the inclined portion 7 of the lens holding frame 3b.

[0060] Next, light rays from a point light source were incident on the optical system of Example 2, and the imaging image was checked. As a result, it was confirmed that there was a deviation in the image of the point light source due to the misalignment of the optical axis direction of lens 11 with respect to the optical axis direction of lens 10. Therefore, while checking the above-described imaging image, the adjustment members 4b arranged at three positions in the circumferential direction of the base lens frame 2 were rotated and advanced and retracted using tools, thereby performing tilt adjustment to align the optical axis direction of lens 11 with the optical axis direction of lens 10, which is the reference optical axis. As a result, the deviation of the image of the point light source disappeared in the above-described imaging image.

Example

[0061] In Example 3, the tilt adjustment mechanism of the lens of the third embodiment according to the present invention was adopted, and the optical system of Example 3 having the structure shown in FIGS. 2 and 3 was assembled. In Example 3, the adjustment member 4c shown in FIG. 8 was used instead of the adjustment member 4a. For lenses 10 and 11, convex lenses as shown in FIG. 3b were used. Also, a structure in which the adjustment member 4c and the base lens frame 2 are screwed together was used. When assembling, the contact position of the convex portion 8 of the lens holding frame 3a was set to the position of the flat portion 13 of the adjustment member 4c.

[0062] Next, when light rays from a point light source were incident on the optical system of Example 3 and the imaging image was observed, it was confirmed that there was a deviation in the image of the point light source due to the misalignment of the optical axis direction of lens 11 with respect to the optical axis direction of lens 10. Therefore, while observing the above-described imaging image, using tools, the adjustment members 4c arranged at three positions in the circumferential direction of the base lens frame 2 were rotated and advanced / retreated to perform tilt adjustment to align the optical axis direction of lens 11 with the optical axis direction of lens 10, which is the reference optical axis. As a result, the deviation in the image of the point light source disappeared in the above-described imaging image.

Industrial Applicability

[0063] The tilt adjustment mechanism for the lens according to the present invention has a relatively simple structure, a small number of components, a small number of assembly man-hours, and a small number of man-hours during tilt adjustment. Therefore, the man-hours and costs during manufacturing can be suppressed. And it is possible to perform tilt adjustment with high precision, and since the shapes of members such as the lens holding frame other than the biasing member do not change even when tilt adjustment is performed, desired optical performance can be ensured. Therefore, it is suitable for optical devices that require high optical performance.

Explanation of Reference Numerals

[0064] 1 Intermediate lens barrel 2 Base lens frame 3a Lens holding frame 3b Lens holding frame 4a Adjustment member 4b Adjustment member 4c Adjustment member 5 Biasing member 6 Biasing member mounting screw 7 Inclined portion 8 Convex portion 9 Hole portion 10 Lens 11 Lens 12 Elastic member 13 Flat portion

Claims

1. A tilt adjustment mechanism for a lens that adjusts the orientation of the optical axis of the lens with respect to the reference optical axis of the lens barrel, a lens holding frame that holds the lens, an adjustment member that can move forward and backward in a direction substantially perpendicular to the reference optical axis of the lens barrel, a base lens frame that can be provided in a state where the adjustment member can move forward and backward in a direction substantially perpendicular to the reference optical axis of the lens barrel, and a biasing member that biases in the direction of the reference optical axis of the lens barrel to press and fix the lens holding frame against the adjustment member, wherein, at the contact portion between the adjustment member and the lens holding frame, at least one of the adjustment member and the lens holding frame has an inclined portion that is inclined with respect to a plane perpendicular to the reference optical axis of the lens barrel. A tilt adjustment mechanism for a lens.

2. The tilt adjustment mechanism for a lens according to claim 1, wherein the adjustment members are arranged at three positions in the circumferential direction of the base lens frame.

3. The tilt adjustment mechanism for a lens according to claim 1, wherein either one of the adjustment member and the lens holding frame that does not have the inclined portion has a convex portion that contacts either one of the adjustment member and the lens holding frame that has the inclined portion at the contact portion.

4. The tilt adjustment mechanism for a lens according to claim 1, wherein the cross-sectional shape perpendicular to the advancing and retreating direction of the adjustment member is line-symmetric with respect to the central axis in the advancing and retreating direction of the adjustment member.

5. The tilt adjustment mechanism for a lens according to claim 1, wherein the movement of the lens holding frame due to the force in a direction substantially perpendicular to the reference optical axis of the lens barrel applied to the lens holding frame when the adjustment member moves forward and backward is restricted by the fitting diameter of the lens holding frame to the base lens frame.

6. A lens barrel, characterized in that it is provided with the tilt adjustment mechanism for a lens according to any one of claims 1 to 5.

Images