JP6357693B2 - Lens device - Google Patents

Description

  The present invention relates to a lens apparatus having a helicoid coupling portion that moves a lens unit forward and backward in the optical axis direction by rotational displacement of an operation ring.

  In general, a lens apparatus is provided with various lens operation mechanisms such as a focus lens operation mechanism for performing focus adjustment. Usually, this type of lens operation mechanism is an operation arranged to be rotatable and displaceable on a fixed barrel of a lens barrel. A ring, a lens unit that holds one or more lenses by a lens frame, and a helicoid coupling that moves the rotational displacement of the operation ring to displace the lens unit in the optical axis direction. . In this case, the helicoid coupling part has a form in which a helicoid male screw provided on the outer peripheral surface of the lens frame and a helicoid female screw provided on the inner peripheral surface of the fixed cylinder are screwed together. In order to realize the above, it is necessary to make so-called backlash at the helicoid coupling portion as small as possible and to approach zero.

  Conventionally, as a means (method) for preventing such backlash, a lens barrel backlash prevention mechanism disclosed in Patent Literature 1 and a backlash prevention method disclosed in Patent Literature 2 are known. The former prevents backlash in the optical axis direction between a pair of helicoid-coupled cylinders, prevents fluctuations in load when rotating one cylinder, and prevents radial backlash at the same time. Specifically, the first cylinder is obtained by dividing the other cylinder that is helicoidally coupled to one of the cylinders to be rotated and divided in the optical axis direction. And the second cylindrical body portion, and the first and second cylindrical body portions are connected in the optical axis direction by a connecting member having an elastic force in the optical axis direction, and by the elastic force of the connecting member. Each of the first and second cylindrical body portions is in contact with one of the cylindrical bodies in different optical axis directions. The latter is intended to realize smooth movement of the lens barrel that moves in the direction of the optical axis and prevention of rattling without adding time and cost to the optical device. The projection lens includes a focus tube and a fixed tube, the focus tube is fitted outside the tip of the fixed tube, and the focus tube and the fixed tube have a helicoid female screw and a helicoid male screw. In addition to the helicoid coupling, the gap between the focus cylinder and the fixed cylinder is filled with grease to which elastic granular material is added.

JP-A-8-304688 JP 2010-160196 A

  However, the conventional means (method) for preventing the above-described backlash has the following problems.

  First, as in Patent Document 1, the means for applying an elastic force from the outside to the helicoid coupling portion has a considerable influence on the rotational displacement and forward / backward displacement of the helicoid coupling portion, and the operation ring is excellent. There is a risk of damaging the operability. In addition, basically, due to the principle of supporting by elastic force, it is not possible to completely prevent backlash. As a result, the effect of maintaining the lens in an accurate position is likely to be diminished depending on the weight of the lens or the angle of the lens, and the request cannot be met when high adjustment accuracy is required for focus adjustment or the like.

  Secondly, the method of storing the filling material in the gap of the helicoid coupling part as in Patent Document 2 has the same problem, and the filling material has a considerable influence on the rotational displacement and the forward / backward displacement of the helicoid coupling part. However, the operability of the operation ring may be affected. In addition, since a process for housing the filling is required, there is a risk that manufacturing ease and manufacturing quality may be impaired, and it is difficult to ensure reliability and stability in long-term use due to deterioration of the filling.

  An object of the present invention is to provide a lens apparatus that solves the problems in the background art.

  In order to solve the above-described problem, the lens device 1 according to the present invention includes one or two or more lenses L1,... By an operation ring 3 that is rotatably disposed on a fixed cylinder 2c of the lens barrel 2 and a lens frame 5. A lens operation mechanism Mc having a lens unit 4 that holds the lens and a helicoid coupling portion 6 that changes the rotational displacement of the operation ring 3 to move the lens unit 4 in the optical axis direction Fc. When the apparatus is configured, it can be fixed to one of the fixed cylinder 2c or the lens frame 5 by a fixing screw 11..., And when the fixing screw 11 is loosened, the surface direction Fd of the surface 12s perpendicular to the optical axis direction Fc. It is formed so as to be displaceable over a predetermined range, and is fixed to the other of the regulation plate 12 having a regulation hole 12h formed in the right-angled surface 12s and the fixed cylinder 2c or the lens frame 5, and the optical axis direction c includes an axis Fs and a position restricting mechanism Ms having an engagement shaft 13 whose position is restricted by being inserted into the restricting hole 12 h. The position restricting mechanism Ms is arranged around the lens frame 5. The fixing screws 11 can be loosened or tightened in a state where at least two sets (Ms...) Are arranged at spaced positions in the direction and the restriction plates 12 are assembled to the intermediate assembly 1m including the lens operating mechanism Mc. It is characterized by being arranged at a position.

  In this case, the focus ring 3f can be applied to the operation ring 3 according to a preferred aspect of the invention. Further, the restriction plate 12 can be fixed at least two positions by fixing screws 11.

  According to the lens device 1 according to the present invention having such a configuration, the following remarkable effects are obtained.

  (1) A restriction plate 12 that can be fixed to one of the fixed cylinder 2c or the lens frame 5 by a fixing screw 11 and has a right angle surface 12s with respect to the optical axis direction Fc, and the other of the fixed cylinder 2c or the lens frame 5. Since the position restricting mechanism Ms having the shaft shaft Fs in the optical axis direction Fc and the engaging shaft 13 that engages with the restricting plate 12 and restricts the position is provided. There is no direct action from the position regulating mechanism Ms. Therefore, good operability of the operation ring 3 can be secured, and at the same time, effective play prevention for the helicoid coupling portion 6 can be achieved. As a result, even when high adjustment accuracy is required for focus adjustment or the like, the request can be sufficiently met.

  (2) This can be realized by additionally assembling a small and simple component that can be mass-produced with respect to the empty space in the lens barrel 2, and even if there is no empty space, it can be realized by slight additional processing. Therefore, it can be carried out easily and at a low cost, and is excellent in versatility such as being easily applicable to existing products. In addition, since it can be realized by a simple engagement structure, it is excellent in durability in long-term use, and further in reliability and stability.

  (3) Since the restriction plate 12 is formed to be displaceable over a predetermined range in the surface direction Fd of the right-angled surface 12s when the fixing screws 11 are loosened, a tracking range when adjusting (setting) the fixing position is secured with a margin. In addition, smooth and reliable adjustment (setting) to the fixed position of the restriction plate 12 can be performed.

  (4) Since the restriction hole 12h is formed in the right-angled surface 12s of the restriction plate 12, and the engagement shaft 13 is inserted into the restriction hole 12h, the entire range in the surface direction of the right-angled surface 12s by one restriction hole 12h. The position restriction mechanism Ms can be implemented with a small number of sets, and can be implemented as the most desirable form from the viewpoint of securing low cost.

  (5) Since the position restricting mechanism Ms is arranged at least two sets (Ms...) Or more at positions separated from each other in the circumferential direction of the lens frame 5, it is possible to further improve the adjustment accuracy such as focus adjustment according to the number of sets. it can. Therefore, it is possible to easily optimize the adjustment accuracy according to the requirements of the various lens devices 1.

  (6) If the focus ring 3f is applied as the operation ring 3 according to a preferred embodiment, the accuracy of focus adjustment can be greatly increased. Therefore, a high-performance lens device or a high-grade lens device that requires particularly high accuracy. It is possible to fully meet the request.

  (7) According to a preferred embodiment, if at least two positions on the regulating plate 12 are fixed by the fixing screws 11..., The fixing strength and the fixing balance with respect to the regulating plate 12 can be increased and fixed. Work for adjusting (setting) the position can be performed accurately and flexibly.

The rear view which specifies the position control mechanism part with which the lens apparatus (intermediate assembly) which concerns on suitable embodiment of this invention is equipped, A perspective view clearly showing the configuration of a position regulating mechanism provided in the lens device, Sectional side view showing the entire structure of the lens device, A side view extracting and showing a position regulating mechanism part provided in the lens device, The side view of the position control mechanism part which shows the state which displaced the lens unit with which the lens apparatus is equipped forward (left direction in a figure), A flowchart showing a procedure for adjusting (setting) an assembly position of a position regulating mechanism provided in the lens device; A cross-sectional side view showing an intermediate assembly of the lens device when adjusting (setting) the assembly position of the position regulating mechanism, Process explanatory drawing at the time of adjusting (setting) the assembly position of the same position regulating mechanism part,

  Next, preferred embodiments according to the present invention will be given and described in detail with reference to the drawings.

  First, in order to facilitate understanding of the present invention, an overview of the entire lens apparatus 1 according to the present embodiment will be described with reference to FIGS. 1 and 3.

  The illustrated lens apparatus 1 is a high-performance lens that requires high adjustment accuracy for focus adjustment, in particular, an interchangeable lens that is attached to and detached from a camera body (not shown). The lens device 1 includes a lens barrel 2 having a fixed cylinder 2c and a rear block 2cr attached to the rear end of the fixed cylinder 2c. The fixed cylinder 2c includes an outer cylinder part 2co and an inner cylinder part 2ci, and a front lens unit 31 is disposed at a front position inside the inner cylinder part 2ci. The front lens unit 31 includes a front lens frame 32 supported by the inner cylinder portion 2ci and a front lens group 33 including four lenses held by the front lens frame 32.

  Furthermore, the lens unit 4 supported by the inner cylinder part 2ci is provided in the rear side position in the inner cylinder part 2ci. The lens unit 4 includes a focus lens frame 5 whose rotational displacement is restricted by the inner cylinder portion 2ci and which is allowed to move forward and backward, and three focus lenses L1, L2, and L3 held by the focus lens frame 5. A focus lens group 8 is provided. In this case, guide slits 36 along the optical axis direction Fc are formed in the inner cylinder portion 2ci, and a part of the ring body 35 provided integrally with the focus lens frame 5 is engaged with the guide slits 36. The lens unit 4 functions as a rear focus method.

  On the other hand, a cut ring space is provided at an intermediate position in the optical axis direction Fc of the outer cylinder portion 2co, and the focus ring 3f for manual operation for performing focus adjustment can be rotationally displaced so as to fill the ring space. Arrange. The focus ring 3 f constitutes the operation ring 3. Further, a helicoid coupling portion 6 is provided between the focus ring 3 f and the lens unit 4. The helicoid coupling portion 6 is formed by a helicoid female screw portion 6i provided on the inner peripheral surface of the focus ring 3f and a helicoid male screw portion 6o provided on the outer peripheral surface of the ring body 35 and screwed into the helicoid female screw portion 6i. Configure.

  On the other hand, a rear block 2cr is attached to the rear end of the outer cylinder portion 2co. The rear block 2cr has a bayonet-type lens mount 41 at the rear end, and is attached to and detached from the mount on the camera body via the lens mount 41. In the example, the rear block 2cr is also provided with a diaphragm ring for adjusting the diaphragm. Further, a rear lens unit 42 is disposed inside the rear block 2cr. The rear lens unit 42 includes a rear lens group 43 including a rear lens frame 43 and four lenses held by the rear lens frame 43. The front end of the rear lens frame 43 is coupled to the rear end of the focus lens frame 5, and the rear lens unit 42 and the lens unit 4 are integrated.

  In the above configuration, the mechanism from the focus ring 3f to the focus lens frame 5 constitutes a basic lens operation mechanism Mc for performing focus adjustment. Thereby, if the focus ring 3f is rotated, the helicoid female screw portion 6i is rotated and displaced. At this time, since the rotational displacement of the helicoid male screw portion 6o is restricted by the guide slits 36 ..., the helicoid male screw portion 6o undergoes motion conversion that moves forward and backward. That is, the lens unit 4 is moved back and forth in the optical axis direction Fc, and focus adjustment is performed.

  By the way, since such a lens operation mechanism Mc is provided with the helicoid coupling | bond part 6, there is not a little backlash. The helicoid coupling part 6 is based on the principle of less play than the normal screw coupling part in principle, but the demand for higher accuracy tends to increase, and on the other hand, to increase the machining accuracy There is a limit. Specifically, even if manufactured by advanced processing technology, an error of about 0.005 [mm] on average occurs at present. Therefore, the lens device 1 according to the present embodiment additionally includes two sets of position restricting mechanism portions Ms and Ns with respect to the lens operating mechanism Mc having the basic configuration as means for preventing the play of the lens operating mechanism Mc. It is configured by adding.

  Next, the position restriction mechanism Ms constituting the main part of the lens device 1 according to the present embodiment will be described with reference to FIGS.

  Although one position restricting mechanism Ms will be described, the other position restricting mechanism Ms can be configured similarly except that it is disposed at a position separated by 180 [°].

  First, components of the position regulation mechanism Ms will be described. The position restriction mechanism Ms includes one restriction plate 12 and one engagement shaft 13 as basic components. Further, two fixing screws 11 and 11 for attaching the regulation plate 12 are used.

  In this case, the regulation plate 12 is formed in a substantially rectangular shape as shown in FIG. 1 by using a rigid material such as a metal material or a plastic material and cutting a plate material having a predetermined thickness. Then, two circular insertion holes 21 and 22 that are separated in the long side direction are formed on one side in the short side direction of the restriction plate 12, and the other side in the short side direction of the restriction plate 12, which is a central position in the long side direction In addition, a restriction hole 12h is formed. As a result, one side of the regulation plate 12 in the short side direction can be fixed to the fixed cylinder 2c by the two fixing screws 11, 11, and at least the other side in the short side of the regulation plate 12 is perpendicular to the optical axis direction Fc. It is formed as a surface 12s.

  At this time, the circular insertion holes 21 and 22 are selected with a diameter through which the screw main body portion 11n of the fixing screw 11 is inserted and, as shown in FIG. Thus, the restriction plate 12 can be displaced over a predetermined range in the surface direction Fd of the right-angled surface 12s when the fixing screws 11 are loosened. Thereby, since the follow-up range when adjusting (setting) the fixed position can be secured with a margin, smooth and reliable adjustment (setting) with respect to the fixed position of the restriction plate 12 can be performed. Furthermore, since the restricting plate 12 is fixed at two positions by the fixing screws 11, 11, the fixing strength and the fixing balance with respect to the restricting plate 12 can be increased, and in addition, the fixing position is adjusted (set). The work can be done accurately and flexibly.

  Further, the restriction hole 12h formed in the right-angled surface 12s is formed by a circular hole through which the engagement shaft 13 is inserted. Thereby, the restriction hole 12h guides the engagement shaft 13 freely in the optical axis direction Fc and restricts it in the surface direction of the right-angled surface 12s. Therefore, the diameter of the restriction hole 12h is selected according to the diameter of the engagement shaft 13, that is, the engagement shaft 13 is allowed to be smoothly displaced with respect to the optical axis direction Fc, and the surface of the right angle surface 12s. Select so that play in the direction is as small as possible. If such a restriction hole 12h is provided, when the engagement shaft 13 is inserted, the entire range in the surface direction of the right-angled surface 12s can be restricted by one restriction hole 12h, so that a sufficient restriction function can be secured. It is possible to implement with a small number of sets, such as realization even if there is only one set of position regulation mechanism Ms, and it can be implemented as the most desirable form from the viewpoint of securing low cost.

  On the other hand, the engagement shaft 13 is formed into a single round bar shape by using a rigid material such as a metal material or a plastic material. In this case, as shown in FIG. 4, the engagement shaft 13 includes a shaft main body 13 m that has an axis Fs in the optical axis direction Fc and that is engaged with the restriction plate 12 and whose position is restricted. Further, an attachment screw portion 13c is integrally formed at one end of the shaft main body portion 13m, and a flange portion 13f having a large diameter is integrally formed between the attachment screw portion 13c and the shaft main body portion 13m.

  Next, a method for assembling the position regulation mechanism Ms and a method for adjusting (setting) the assembly position will be described with reference to FIGS.

  First, the lens device 1 according to the present embodiment uses two sets of position restricting mechanisms Ms... And is arranged at positions spaced apart by 180 ° in the radial direction of the lens barrel 2 as shown in FIG. Set up. As described above, if at least two sets (Ms...) Or more of the position restriction mechanism portions Ms are arranged at spaced positions, the adjustment accuracy such as focus adjustment can be further increased according to the number of sets. Therefore, it is possible to easily optimize the adjustment accuracy according to the requirements of the various lens devices 1.

  Hereinafter, an assembly method and an assembly position adjustment (setting) method will be described with reference to the flowchart shown in FIG.

  Although one position restricting mechanism Ms will be described, the other position restricting mechanism Ms can be similarly assembled and adjusted (set). First, in the pre-assembly process, necessary assembly on the side of the fixed cylinder 2c including the lens unit 4 is performed to obtain an intermediate assembly 1m shown in FIG. 7 (step S1). The intermediate assembly obtained in step S1 is in a state in which the regulating plate 12, the fixing screws 11, 11 and the engagement shaft 13 are removed from the intermediate assembly 1m shown in FIG.

  Then, the engagement shaft 13 is attached to the focus lens frame 5 in the lens unit 4 (step S2). In this case, as shown in FIG. 5, the mounting screw portion 13c of the engagement shaft 13 is provided on the step surface portion of the focus lens frame 5 of the lens unit 4, that is, the step surface portion 5s perpendicular to the optical axis direction Fc. A screw hole 25 that can be screwed is formed, and a mounting screw portion 13 c is screwed into the screw hole 25. That is, the engagement shaft 13 is fixed to the lens frame 5. As a result, the engagement shaft 13 has the axis Fs in the optical axis direction Fc and protrudes rearward. The step surface portion 5s may use the step surface of the existing focus lens frame 5 as it is, or may be formed separately when an appropriate step surface does not exist. The focus lens frame 5 is a concept that includes not only the lens frame 5m that directly holds the lenses L1, but also all members that are integrally attached to the lens frame 5m.

  On the other hand, when the attachment of the engagement shaft 13 is completed, the restriction plate 12 is attached to the rear end portion of the inner cylinder portion 2ci of the fixed cylinder 2c by the fixing screws 11 and 11. In this case, as shown in FIG. 2, a mounting recess 2cc that is recessed in the optical axis direction Fc is formed in a cutout shape at the rear end of the inner cylinder portion 2ci, and a fixing screw 11 is screwed into the mounting recess 2cc. A pair of spaced apart screw holes is formed. In assembly, first, the shaft body 13m (engagement shaft 13) is inserted through the restriction hole 12h of the restriction plate 12 (step S3). Then, the fixing screws 11 are passed through the circular insertion holes 21 and 22 of the restricting plate 12 and screwed into the screw holes of the mounting recesses 2cc provided in the inner tube portion 2ci, whereby the restricting plate 12 is attached to the fixed tube 2c. (Step S4). At this time, it is held in a temporarily fixed state so that the regulating plate 12 can be displaced in the surface direction Fd with a slight external force without being completely fixed (step S5).

  Thereafter, the focus ring 3f is rotated over the entire operation range (step S6). Thereby, as shown in FIG. 8, the engagement shaft 13 (shaft main body part 13m) can be displaced over the stroke range between the front-end position shown as a continuous line, and the rear-end position shown as a virtual line. Therefore, if the shaft main body 13m is reciprocally displaced within the stroke range an appropriate number of times, the regulation plate 12 is automatically adjusted (set) to the optimum position corresponding to this displacement.

  Based on this principle, the fixing screws 11 and 11 are tightened in the direction of the arrow Fr in FIG. 8 or loosened as necessary while confirming that the focus ring 3f can be rotated and operated smoothly. The fixing screws 11, 11 are tightened (steps S6, S7, S8, S9, S5...). Then, finally, the fixing screws 11 are completely tightened. Thereby, the regulation plate 12 can be fixed to the fixed cylinder 2c. This state is the intermediate assembly 1m shown in FIG. When the attachment of the restriction plate 12 is completed, a subsequent pre-assembly process is performed (steps S10 and S11). In the rear and front assembly process, the remaining parts such as the rear block 2cr and the rear lens unit 42 are assembled. Thereby, the target lens apparatus 1 shown in FIG. 3 can be obtained.

  Therefore, according to such a lens device 1 according to the present embodiment, the restriction that can be fixed to one of the fixed cylinder 2c or the lens frame 5 by the fixing screw 11 and has a right angle surface 12s with respect to the optical axis direction Fc. A plate 12 and an engagement shaft 13 that is fixed to the other of the fixed cylinder 2c or the lens frame 5 and has an axis Fs in the optical axis direction Fc and that is engaged with the restriction plate 12 and whose position is restricted. Since the position restricting mechanism Ms is provided, no direct action from the position restricting mechanism Ms on the helicoid coupling portion 6 occurs. Therefore, good operability of the operation ring 3 can be secured, and at the same time, effective play prevention for the helicoid coupling portion 6 can be achieved. As a result, even when high adjustment accuracy is required for focus adjustment or the like, the request can be sufficiently met. In particular, in the case of the illustrated embodiment, if the position restriction mechanism Ms is not provided, an error of about 0.005 [mm] on average occurs, but by providing two position restriction mechanisms Ms and Ms. The maximum error was 0.002 [mm] or less.

  Further, it can be realized by additionally assembling a small and simple component that can be mass-produced with respect to an empty space in the lens barrel 2, and even if there is no empty space, it can be realized by a slight additional processing. Therefore, it can be carried out easily and at a low cost, and is excellent in versatility such as being easily applicable to existing products. In addition, since it can be realized by a simple engagement structure, it is excellent in durability in long-term use, and further in reliability and stability. In addition, since the focus ring 3f is applied as the operation ring 3, it is possible to dramatically improve the accuracy of focus adjustment, and sufficiently meet the demands for high-performance lens devices and high-grade lens devices that require particularly high accuracy. Can do.

  Although the preferred embodiment has been described in detail above, the present invention is not limited to such an embodiment, and the detailed configuration, shape, material, quantity, technique, and the like do not depart from the gist of the present invention. It can be changed, added, or deleted arbitrarily.

  For example, although the embodiment in which the restriction plate 12 is attached to the fixed cylinder 2c and the engagement shaft 13 is attached to the lens frame 5 is illustrated, the restriction plate 12 is attached to the lens frame 5 and the engagement shaft 13 is attached to the fixed cylinder 2c. Form may be sufficient. Moreover, although the case where the focus ring 3f was applied as the operation ring 3 was illustrated, other operation rings 3 such as a zoom ring may be used. On the other hand, the restriction plate 12 is illustrated as having two positions fixed by the fixing screws 11, 11. However, the restriction plate 12 does not exclude one place, and may be three or more places. In addition, although the case where the two position restricting mechanism portions Ms and Ms are disposed at positions separated by 180 [°] is illustrated as the position restricting mechanism portion Ms, three or more pairs may be provided. Furthermore, when the position restricting mechanism portion Ms is configured, the case where the restricting holes 12h are formed in the right-angled surface 12s of the restricting plate 12 is shown. However, when two or more sets of the position restricting mechanism portions Ms. Other forms of implementation are possible, such as engaging a notch in the shape of a letter.

  The lens device 1 according to the present invention can be used not only for interchangeable lenses but also for camera-integrated lenses, and for various types of lenses such as standard lenses, zoom lenses, and macro lenses. The camera to be used can also be used for various types of cameras such as a film camera, a digital camera, and a video camera.

  DESCRIPTION OF SYMBOLS 1: Lens apparatus, 1m: Intermediate assembly, 2: Lens barrel, 2c: Fixed cylinder, 3: Operation ring, 3f: Focus ring, 4: Lens unit, 5: Lens frame, 6: Helicoid coupling part, 11 ...: Fixing screw, 12: restriction plate, 12s: right angle surface, 12h: restriction hole, 13: engagement shaft, L1 ...: lens, Fc: optical axis direction, Fs: axial center, Fd: surface direction, Mc: lens operation mechanism , Ms ...: Position restriction mechanism

Claims (3)

  An operation ring arranged to be rotatable and displaceable on a fixed barrel of the lens barrel, a lens unit that holds one or more lenses by a lens frame, and the lens by converting the rotational displacement of the operation ring to motion In a lens apparatus comprising a lens operating mechanism having a helicoid coupling portion that displaces the unit in the optical axis direction, the lens device can be fixed to one of the fixed cylinder or the lens frame with a fixing screw, and the fixing screw is loosened. And is formed so as to be displaceable over a predetermined range in a plane direction perpendicular to the optical axis direction, and is fixed to the other of the regulation cylinder and the fixed cylinder or the lens frame. And a position restriction mechanism having an axis in the optical axis direction and an engagement shaft whose position is restricted by being inserted through the restriction hole. Loosen the fixing screw in a state in which at least two sets of control mechanisms are disposed at spaced positions in the circumferential direction of the lens frame, and the restriction plate is assembled to an intermediate assembly including the lens operating mechanism. A lens device, wherein the lens device is arranged at a position where tightening is possible.   The lens device according to claim 1, wherein the operation ring is a focus ring.   The lens device according to claim 1, wherein the restriction plate fixes at least two positions with fixing screws.

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