JP5424838B2 - Lens device filter mechanism - Google Patents

Description

  The present invention relates to a filter mechanism of a lens device, and more particularly to a filter mechanism applied to a CCTV lens used mainly in a CCTV (Closed Circuit Television) camera (monitoring camera) for monitoring purposes.

  2. Description of the Related Art Lens devices such as CCTV lenses used in surveillance cameras are known that include a filter mechanism that switches and inserts multiple types of filters such as ND filters and IR filters on the optical path (for example, Patent Document 1, (See 2nd grade).

  The filter mechanism of the present invention is a filter mechanism in which a filter frame (turret) that holds a plurality of filters is rotated and a filter that is inserted into an optical path of an optical system can be switched as in Patent Document 1. For example, a disk-shaped filter frame arranged in a direction orthogonal to the optical axis of the optical system is provided, and the center axis of the filter frame is parallel to the rotation axis as a position shifted from the optical axis of the optical system. A plurality of openings (filter installations) in which various filters are mounted at the position of the filter frame that is supported rotatably and that passes through the optical path of the optical system when the filter frame is rotated around the rotation axis at a predetermined rotation angle. Part). Then, by rotating the filter frame with a motor that engages with a gear formed at the peripheral edge of the filter frame, one of the plurality of filters held by the filter frame is switched to the optical path of the optical system. It can be inserted.

  In this type of filter mechanism, the filter frame is rotatably supported in a state of being sandwiched between a mounting frame (rear side) and a holding frame (front side) arranged in the front and rear in the optical axis direction. A support shaft projects from the rear surface side at the center position of the frame, and a bearing hole is formed on the front surface side. On the other hand, a bearing hole is formed in the mounting frame, and a support shaft on the rear surface of the filter frame is fitted into the bearing hole. Further, a support shaft projects from the holding frame, and the support shaft is fitted into a bearing hole on the front surface of the filter frame. Thereby, the filter frame is rotatably supported in a state of being sandwiched between the attachment frame and the holding frame.

JP 2001-273036 A JP 2004-347624 A

  By the way, the attachment frame and the holding frame arranged before and after the filter frame are fixed to a predetermined position of the lens barrel member constituting the lens barrel with screws or the like. Therefore, if the filter mechanism of all products is not designed so that the filter frame is loose, the filter frame may be narrowed between the mounting frame and the holding frame due to manufacturing errors depending on the product. . At this time, there is a problem that the filter frame does not rotate smoothly. When the filter frame is rotated by a motor, the power consumption of the motor becomes excessive.

  On the other hand, when the filter frame is loose as described above, the inclination and position of the filter frame with respect to the optical axis direction vary depending on the attitude of the lens device, and the connection state between the filter frame and the motor (formed on the filter frame). The filter frame does not rotate smoothly due to the deterioration of the connection state between the gear to be transmitted and the gear that transmits power to the filter frame, or the plate portion of the filter frame being in surface contact with the mounting frame or the holding frame. Problems arise. If the connection between the filter frame and the motor is poor, there is a problem such as abnormal noise in addition to the problem of excessive power consumption of the motor.

  The present invention has been made in view of such circumstances. In a filter mechanism in which a filter frame that holds a plurality of filters is rotated so that a filter that is inserted into an optical path of an optical system can be switched, the posture of the lens device can be changed. However, an object of the present invention is to provide a filter mechanism for a lens apparatus in which a filter frame rotates smoothly.

  In order to achieve the object, the filter mechanism of the lens device according to claim 1 is a lens in which a filter inserted into an optical path of an optical system can be switched by rotating a filter frame of a plate-like body that holds a plurality of filters. In the filter mechanism of the apparatus, a first frame and a second frame that are arranged before and after the filter frame and rotatably support the filter frame, and the filter frame on a rotation axis of the filter frame. And the first frame is formed with a support shaft, and the other is formed with a bearing hole that fits with the support shaft substantially without play, and the filter frame on the rotation axis of the filter frame. A support shaft is formed on one of the second frame and a bearing hole having a size having the support shaft and play is formed on the other, and protrudes annularly on the front and rear surfaces of the filter frame. Ridge Are formed at a plurality of predetermined positions on the annular line facing the ridge ring in the first frame and the second frame, and the bulges that are raised from the surroundings are formed. The inclination and displacement of the filter frame are limited within a range in which the protruding ring contacts one of the raised portions of the second frame.

  That is, according to the present invention, in order to smoothly rotate the filter frame, the support shaft and the bearing hole are engaged with one of the first frame and the second frame sandwiching the filter frame and having a backlash. I try to let them. On the other hand, in this case, depending on the posture of the lens device, the filter frame may come into surface contact with the first frame or the second frame and the filter frame does not rotate smoothly due to frictional resistance, or the filter frame is rotated by a motor. In some cases, the connection between the filter frame and the motor may be poor and the filter frame may not rotate smoothly. However, the protrusion ring projecting on both sides of the filter frame, the first frame and the second frame Because the filter frame tilt and displacement are limited (position regulation) by a minute frictional resistance due to the point contact with the raised portion protruding from the frame, the filter frame rotates smoothly regardless of the orientation of the lens device. become.

  The filter mechanism of the lens device according to claim 2 is the invention according to claim 1, wherein the protruding ring is raised in a substantially circular shape in cross section, and the raised portion is raised in a shape having a flat surface at the tip. It is a feature. This invention shows one form of the preferable shape of a protruding ring and the protruding part contact | abutted to this.

  According to a third aspect of the present invention, in the filter mechanism of the lens device according to the first or second aspect, the filter frame has a gear that engages with a motor and is rotated by a driving force of the motor. It is said. When driving the filter frame with a motor, if the tilt or displacement of the filter frame is large, the connection state with the motor will deteriorate and the filter frame will not rotate smoothly (the problem of excessive motor power consumption) Since problems such as the generation of abnormal noise occur, it is a great effect that the filter frame smoothly rotates by limiting the inclination and displacement of the filter frame as in the first aspect of the invention.

  According to the filter mechanism of the lens device according to the present invention, the filter frame rotates smoothly regardless of the posture of the lens device.

The perspective view which showed the external appearance of the lens apparatus provided with the filter mechanism which concerns on this invention. The perspective view which extracted and showed the filter mechanism based on this invention installed in the rear-end part of the lens apparatus of FIG. The disassembled perspective view which decomposed | disassembled and showed the filter frame of the filter mechanism, the attachment frame, and the holding frame from the front side. The disassembled perspective view which decomposed | disassembled and showed the filter frame of the filter mechanism, the attachment frame, and the holding frame from the front side. Sectional drawing cut | disconnected in the vertical direction along the rotating shaft of the filter frame in FIG. The perspective view which expanded the filter frame and its part, and showed it from the front side. The perspective view which expanded and showed the attachment frame and its one part from the front side. The perspective view which expanded and showed the holding frame and its part from the back side. The principal part expanded sectional view which cut | disconnected the filter frame along the rotating shaft in the position which passes the protruding part of an attachment frame and a holding frame.

  Hereinafter, preferred embodiments of the filter mechanism of the lens device according to the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a perspective view showing an overview of a lens apparatus provided with a filter mechanism according to the present invention. A lens apparatus 10 shown in FIG. 1 is a lens apparatus (CCTV lens) used for a CCTV camera used for monitoring or the like, for example, and although not described in detail, a fixed lens barrel that forms the main part of the lens barrel Various components are assembled in the frame 12, and lens groups such as a focus lens group and a zoom lens group that constitute an optical system for forming a subject image along the central axis (optical axis A) are arranged. Yes. And the filter mechanism 14 which concerns on this invention is installed in the rear-end part of the lens barrel.

  FIG. 2 is a perspective view showing the filter mechanism 14 according to the present invention installed at the rear end of the lens device 10 of FIG. As shown in the figure, the filter mechanism 14 is supported by a lens barrel frame 20 fixed to the rear end portion of the lens barrel, and mainly includes a filter frame 30, an attachment frame 50, a holding frame 60, and a stepping motor 70. Has been. FIGS. 3 and 4 are exploded perspective views of the filter frame 30, the mounting frame 50, and the holding frame 60. FIG. 3 shows the lens device 10 from an oblique front side (object side). FIG. 4 is a perspective view showing the lens device 10 from an oblique rear side.

  As shown in FIGS. 2 to 4, the mounting frame 50 is disposed on the rear side of the filter frame 30 and is screwed to the lens barrel frame 20 with screws 22, 22, 22. The holding frame 60 is disposed on the front side of the filter frame 30, and is screwed to the lens barrel frame 20 together with the stepping motor 70 and the mounting frame 50 by screws 24, and is screwed to the lens barrel frame 20 together with the mounting frame 50 by screws 26. ing. As a result, the mounting frame 50, the holding frame 60, and the stepping motor 70 are fixed at predetermined positions with respect to the lens barrel frame 20. The filter frame 30 is formed of a disk-like plate-like body, and will be described in detail later. The filter frame 30 is pivotally supported between the mounting frame 50 and the holding frame 60 so as to be rotatable about its central axis as a rotation axis B. ing.

  The optical path of the optical system is formed in the periphery of the optical axis A, the holding frame 60 is cut out in a shape that does not block the portion that becomes the optical path, and the mounting frame 50 has an opening 52 formed in the portion that becomes the optical path. ing. In the filter frame 30, when the filter frame 30 is rotated about the rotation axis B, a predetermined type of filter is installed at the position of the plate portion 32 that becomes an optical path at predetermined rotation angles (approximately every 120 degrees). The filter installation portions 34A, 34B, and 34C are formed as openings. The filter installation portions 34A, 34B, and 34C in FIGS. 2 to 4 are not illustrated with filters that are actually installed, and are in a through state (a state in which nothing is installed). The remaining two are provided with ND filters having different light attenuation rates. In addition, the kind of filter installed in filter installation part 34A, 34B, 34C is arbitrary.

  A gear 36 is formed on the periphery of the filter frame 30, and a gear 72 (see FIG. 4) provided on the rotation shaft of the stepping motor 70 is meshed with the gear 34, and the filter is driven by the driving force of the stepping motor 70. The frame 30 rotates around the rotation axis B. Therefore, by rotating the filter frame 30 by the stepping motor 70, the filter installation portions 34A, 34B, and 34C where the desired filters of the filter frame 30 are installed are installed at positions that serve as optical paths, and the filters are optical paths of the optical system. And the type of filter to be inserted into the optical path of the optical system can be switched. In the present embodiment, the filter mechanism for rotating the filter frame 30 by the stepping motor 70 is shown. However, the motor for rotating the filter frame 30 may not be a stepping motor, but may be another type of motor. The present invention can also be applied to a mechanism for manually rotating the frame 30.

  Next, the support structure of the filter frame 30 that is pivotally supported between the mounting frame 50 and the holding frame 60 will be described in detail. FIG. 5 is a cross-sectional view taken in the longitudinal direction along the rotation axis B of the filter frame 30 in FIG. 1, and the right side in the drawing indicates a direction that is the front side (object side) of the lens device 10. As shown in the figure, a cylindrical support shaft 38 projects from the rear surface side at the center position of the filter frame 30 (position of the rotary shaft B), and a cylindrical bearing hole (cross section is circular) on the front surface side. 40 is formed.

  On the other hand, on the rear surface side of the holding frame 60 disposed in front of the filter frame 30, a cylindrical support shaft 62 is projected at the position of the rotation axis B, and the support shaft 62 is the front surface of the filter frame 30. The side bearing hole 40 is fitted with almost no gap.

  Further, a cylindrical bearing hole 54 is formed at the position of the rotary shaft B on the front side of the mounting frame 50 disposed behind the filter frame 30, and the bearing hole 54 is a support shaft of the holding frame 60. In a state in which 62 is fitted in the bearing hole 40 of the filter frame 30, even a large manufacturing error is formed with a diameter larger than that of the support shaft 38 to the extent that the support shaft 38 on the rear surface side of the filter frame 30 is surely fitted. At the same time, the filter frame 30 is formed with a depth that surely has a play in the direction of the rotation axis B. That is, the bearing hole 54 is formed to have a backlash with the support shaft 38. As a result, the problem that the filter frame 30 does not rotate smoothly due to the narrow pressure between the mounting frame 50 and the holding frame 60 is prevented. Note that the gap between the attachment frame 50 and the holding frame 60 at the portion where the plate portion 32 of the filter frame 30 is disposed is larger than the width (thickness) of the plate portion 32 between the attachment frame 50 and the holding frame 60. Installation interval (shape) is designed.

  On the other hand, with respect to the backlash of the filter frame 30 as described above, the connection state between the gear 36 on the periphery of the filter frame 30 and the stepping motor 70 is kept good regardless of the posture of the lens device 10 and the like, and the filter frame 30. In order to prevent the plate portion 32 from coming into surface contact with the mounting frame 50 or the holding frame 60, the filter frame 30 is provided between the filter frame 30 and the mounting frame 50 and between the filter frame 30 and the holding frame 60. A restricting structure is provided to limit the play (tilt and displacement) within a predetermined range.

  6 is an enlarged perspective view showing the filter frame 30 and a part thereof from the front side, and FIG. 7 is an enlarged perspective view showing the mounting frame 50 and a part thereof from the front side. FIG. 8 is an enlarged perspective view showing the holding frame 60 and a part thereof from the rear side.

  As shown in FIG. 6, the front side 32A and the rear side 32B of the plate part 32 of the filter frame 30 are respectively protruded from the filter installation parts 34A, 34B, 34C to the outer peripheral side, and the front side protrusions having a substantially semicircular cross section. A strip ring 42 and a rear projection ring 44 (only the front projection ring 42 is shown in FIG. 6 and the rear projection ring 44 is shown in FIGS. 4 and 9) are formed.

  On the other hand, as shown in FIG. 7, on the front surface of the mounting frame 50, a raised portion 56 having a flat surface at the front end portion raised from the periphery at three positions on the annular line facing the rear surface-side protruding ring 44 of the filter frame 30. , 56, 56 (see enlarged view) are formed. Further, as shown in FIG. 8, on the front surface of the holding frame 60, raised portions 64, 64, 64, 46 that protrude from the periphery at four positions on the annular line facing the front-side protruding ring 42 of the filter frame 30. Is formed.

  FIG. 9 shows a cross-sectional view of the filter frame 30 cut along the rotation axis B at a position passing through the raised portions 56 and 64. As shown in the figure, the front-side ridge ring 42 formed on the front surface 32A of the plate portion 32 of the filter frame 30 is in a state where its tip end portion is substantially in contact with the raised surface of the raised portion 64 of the holding frame 60. Thus, the rear-side protruding ring 44 formed on the rear surface 32B of the plate portion 32 of the filter frame 30 is in a state in which the front end portion thereof is substantially in contact with the raised surface of the raised portion 56 of the mounting frame 50. According to this, the play of the filter frame 30 (inclination with respect to the rotation axis B and displacement in the direction of the rotation axis B) is such that one of the front side protrusion ring 42 and the rear side protrusion ring 44 is raised. 64 or a narrow range until it comes into contact with the raised portion 56.

  Therefore, the connection state between the gear 36 at the peripheral edge of the filter frame 30 and the stepping motor 70 is kept good. Further, even when the front-side ridge ring 42 or the rear-side ridge ring 44 is in contact with the raised portion 64 or the raised portion 56, the contact area is small, so that only a small frictional resistance is generated when the filter frame 30 is rotated. It does not occur, and the generation of large frictional resistance is also prevented. Thereby, the filter frame 30 rotates smoothly irrespective of the attitude | position of the lens apparatus 10. FIG.

  Note that the front side protrusion ring 42 and the rear side protrusion ring 44 of the filter frame 30 are formed at different radial positions with respect to the rotation axis B (the central axis of the filter frame 30). The position may be any position as long as it is on a radius where the other components of the filter frame 30 are not formed. In FIG. 9, the raised portion 56 and the raised portion 64 are present in the same cross section, but are not actually in the same cross section, and the positions where they are provided are irrelevant to each other. Further, in the above embodiment, the front side protrusion ring 42 and the rear side protrusion ring 44 have a substantially semicircular cross section, and the raised parts 56 and 64 have a flat surface at the tip part. Is not limited to this. Further, the number of the raised portions 56 and the raised portions 64 provided on each of the attachment frame 50 and the holding frame 60 is within a range in which the frictional resistance with the front-side protruding ring 42 or the rear-side protruding ring 44 is not a problem. Any number of locations may be provided.

  As described above, in the above embodiment, the support shaft 38 is provided on the rear surface side of the filter frame 30 and the bearing hole 40 is provided on the front surface side, but conversely, the same as the support shaft 38 on the front surface side of the filter frame 30. A bearing hole similar to the bearing hole 40 is provided on the rear surface side of the support shaft, a support shaft that substantially fits in the bearing hole on the rear surface side of the filter frame 30 is provided on the mounting frame 50, and the filter frame 30 is provided on the holding frame 60. You may form the bearing hole which fits the support shaft of the front side of this with a backlash. Further, the support shaft and the bearing hole may be provided between the filter frame 30 and the mounting frame 50 and between the filter frame 30 and the holding frame as long as they are paired. A mode in which support shafts are formed to protrude on both sides of the frame 30 is also possible. Further, the support shaft and the bearing hole formed so as to have backlash (in the above embodiment, the support shaft 38 on the rear surface side of the filter frame 30 and the bearing hole 54 of the mounting frame 50) are not necessarily formed. In this case, it can be considered that the support shaft and the bearing hole are formed so as to have the limit play, and correspond to the support shaft and the bearing hole formed so as to have the play.

  Moreover, although the case where this invention was applied to the filter mechanism of a CCTV lens was demonstrated in the said embodiment, the filter mechanism which concerns on this invention is applicable not only to a CCTV lens but to the filter mechanism of arbitrary types of lens apparatuses. .

  DESCRIPTION OF SYMBOLS 10 ... Lens apparatus, 12 ... Fixed lens barrel frame, 14 ... Filter mechanism, 20 ... Lens barrel frame, 30 ... Filter frame, 32 ... Plate part, 34A, 34B, 34C ... Filter installation part (opening), 36 ... Gear, DESCRIPTION OF SYMBOLS 38 ... Support shaft, 40 ... Bearing hole, 42 ... Front side protrusion ring, 44 ... Rear side protrusion ring, 50 ... Mounting frame, 52 ... Opening, 54 ... Bearing hole, 56, 64 ... Raised part, 60 ... Holding Frame, 62 ... support shaft, 70 ... stepping motor, A ... optical axis, B ... rotary axis

Claims (3)

In the filter mechanism of the lens device, in which the filter inserted into the optical path of the optical system can be switched by rotating the filter frame of the plate-like body that holds a plurality of filters,
A first frame and a second frame which are arranged before and after the filter frame and which are rotatably supported with the filter frame sandwiched therebetween;
On the rotating shaft of the filter frame, a support shaft is formed on one of the filter frame and the first frame, and a bearing hole is formed on the other so as to fit with the support shaft almost without play.
On the rotating shaft of the filter frame, a support shaft is formed on one of the filter frame and the second frame, and a bearing hole having a size having the support shaft and play is formed on the other,
An annular projecting ring is formed on the front surface and the rear surface of the filter frame, and the first frame and the second frame protrude from the surroundings at predetermined positions on the annular line facing the projecting ring. A ridge is formed,
In the lens device, the inclination and displacement of the filter frame are limited within a range in which the protruding ring abuts on one of the raised portion of the first frame and the raised portion of the second frame. Filter mechanism.   2. The filter mechanism of the lens device according to claim 1, wherein the protruding ring is raised in a substantially circular shape in cross section, and the raised portion is raised in a shape having a flat surface at the tip.   The filter mechanism of the lens device according to claim 1, wherein the filter frame has a gear that engages with a motor and is rotated by a driving force of the motor.

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