JP2005062432A - Lens device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens device where a plurality of lenses are incorporated and fixed in a holding frame in a state where they are positioned each other without performing thermal caulking. <P>SOLUTION: The tapered recessed part 51 of a front lens 41 is fitted to the tapered projecting part 57 of a middle lens 42 so as to position the lenses, and the tapered recessed part 61 on the back side of the lens 42 is fitted to the tapered projecting part 67 of a rear side lens 43 so as to position the lenses. In such a state, the lenses are housed in the holding barrel 71 of the holding frame 45, and a pressing frame 46 is housed in the frame 45 so as to be fit to the holding barrel 71 from the back side, then the pawl 83 of the frame 46 is made to get over the inclined surface 76 of the engaging rib 75 of the holding frame 45 and engaged in a recess 77. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a lens apparatus, and more particularly, to a lens apparatus assembled so that a plurality of lenses are overlapped.

  A lens barrel used in a video camera or the like is arranged from four lens groups: a lens group constituting an objective lens from the front to the rear, an image frame setting lens group, a correction lens group, and a focus lens group. Then, an image pickup device composed of a CCD is arranged behind the rear focus lens group. Here, the second image frame setting lens group and the fourth focusing lens group from the front must be moved in the optical axis direction for the zoom operation and the focus operation, respectively. Therefore, these lens groups are mounted on a moving frame, mounted so as to be movable along the guide shaft, and moved in the optical axis direction by a moving motor (see Japanese Patent No. 3120454).

  A glass lens is used as a lens that is attached to and moved by the moving frame as described above, and these glass lenses are housed in a holding portion of a holding frame made of a synthetic resin molding, and the end of the cylindrical portion of the holding frame is attached The glass lens was fixed to the holding frame by heat deformation and caulking.

  However, according to such a structure, the cost of the lens device increases because the cost of the glass lens itself increases. Further, since the glass lens is heavy, the weight of the lens device also increases. Furthermore, the glass lens has no freedom in shape, and it is impossible to form a crimped shape such as a boss or a hole. Accordingly, there is only a method for fixing the lens by deforming and fixing a required portion of the plastic member on the holding frame side by a method such as heat caulking.

  In addition, when fixing the glass lens to the holding frame, the outer peripheral side of the optically required aperture must be caulked by heat caulking or the like, and the caulking space is the outer peripheral part of the lens. Therefore, the diameter of the lens increases correspondingly, and the weight increases as the lens becomes larger. In addition, the method of fixing the glass lens by heat-clamping to the holding frame as described above requires heat-clamping equipment, and it is necessary to determine the conditions of heat-clamping for each lens. There are drawbacks that can be cumbersome.

  Therefore, as disclosed in Japanese Patent Laid-Open No. 2002-182089, a method has been proposed in which a boss is raised on the plastic lens side and the boss is heat-capped. That is, it has a plastic lens in which a plurality of fixing protrusions are integrally provided, and a lens holding portion in which a plurality of support holes having different opening shapes and roles are provided, and the lens is inserted into the support holes. The tip of the fixed protrusion is crushed into an umbrella shape by heat treatment, etc., and fixed to the lens barrel in a predetermined positional relationship. A plastic lens is used in order to reduce costs and weight, and a plastic lens is used. In this case, adverse effects such as distortion are prevented.

  However, such a lens barrel requires heat caulking for heat caulking the projections of the plastic lens. Further, it is necessary to determine the conditions for heat caulking for each lens, and there is a drawback that the assembling work becomes troublesome.

Japanese Patent No. 3120454 (Regarding the arrangement structure of lenses of a lens barrel of a video camera, column 3, lines 29 to 48 and FIG. 1) JP 2002-182089 A (Plastic Lens Fixing Structure to Holding Frame)

  An object of the present invention is to provide a lens device in which a plurality of lenses are easily and stably positioned relative to each other.

  Another object of the present invention is to provide a lens device in which a plurality of lenses are held in a holding frame while being positioned with respect to each other.

  Still another object of the present invention is to provide a lens device in which a plurality of lenses are accommodated in a holding frame and pressed without being subjected to heat caulking.

  Still another object of the present invention is to provide a lens apparatus including a plurality of lenses that is easy to assemble without having to condition each lens.

  The above-described problems and other problems of the present invention will be made clear by the gist and embodiments of the invention described below.

The main invention of the present application is a lens device assembled so as to overlap a plurality of lenses.
A tapered concave portion is formed in one lens adjacent to each other in the axial direction, a tapered convex portion is formed in the other adjacent lens, and the tapered concave portion and the tapered convex portion are fitted to each other in a concave-convex manner. The present invention relates to a lens device that performs positioning in a radial direction.

  Here, it is preferable that the lenses that are adjacent to each other and perform positioning in the radial direction by the tapered concave portion and the tapered convex portion are plastic lenses. Moreover, it is preferable that the taper angle of the tapered concave portion and the taper angle of the tapered convex portion are substantially equal to each other. In addition, it is preferable that a fixed diaphragm is sandwiched between adjacent lenses.

Another main invention of the present application is a lens device constructed by assembling a plurality of lenses so as to overlap each other.
A stepped concave portion is formed in one lens adjacent to each other in the axial direction, a stepped convex portion is formed in the other adjacent lens, and the stepped concave portion and the stepped convex portion are fitted to each other in a concave-convex manner. The present invention relates to a lens device that performs positioning in a radial direction.

  Here, it is preferable that the lenses that are adjacent to each other and perform positioning in the radial direction by the step-shaped concave portion and the step-shaped convex portion are plastic lenses. Moreover, it is preferable that the diameter of the step-shaped concave portion and the diameter of the step-shaped convex portion are substantially equal to each other. In addition, it is preferable that a fixed diaphragm is sandwiched between adjacent lenses.

Still another main invention of the present application is a lens device constructed by assembling a plurality of lenses so as to overlap each other.
A tapered concave portion is formed in one lens adjacent to each other in the axial direction, a tapered convex portion is formed in the other adjacent lens, and the tapered concave portion and the tapered convex portion are fitted to each other in a concave-convex manner. Perform radial positioning,
The present invention relates to a lens apparatus in which the plurality of lenses are housed in a holding frame and the plurality of lenses are pressed by a holding frame.

  Here, it is preferable to press the claw provided on one of the presser frame and the holding frame by engaging with an engaging hole provided on the other. Moreover, it is preferable that the engagement by the claw and the engagement hole is a bayonet type engagement.

Still another main invention of the present application is a lens device constructed by assembling a plurality of lenses so as to overlap each other.
A stepped concave portion is formed in one lens adjacent to each other in the axial direction, a stepped convex portion is formed in the other adjacent lens, and the stepped concave portion and the stepped convex portion are fitted to each other in a concave-convex manner. Perform radial positioning,
The present invention relates to a lens apparatus in which the plurality of lenses are housed in a holding frame and the plurality of lenses are pressed by a holding frame.

  Here, it is preferable to press the claw provided on one of the presser frame and the holding frame by engaging with an engaging hole provided on the other. Moreover, it is preferable that the engagement by the claw and the engagement hole is a bayonet type engagement.

  In general, by changing the lens material from glass to plastic, the cost and weight of the lens device can be reduced. Here, as a method of holding the lens in the lens barrel, there is a method of caulking the rib on the lens barrel side as in the case of using a conventional glass lens. There is also a method in which a boss is formed on the plastic lens side and the boss is fixed by heat caulking. On the other hand, the preferred embodiment of the present application utilizes the wide flexibility of the shape of the plastic lens, and fixes the above ribs and bosses without heat caulking. is there.

  That is, in a preferred aspect of the present invention, in order to obtain the positioning accuracy of a plurality of plastic lenses, a taper portion is provided in the plastic lens, and the taper portions are positioned by receiving each other to form an alignment structure. is there. In addition, in order to hold and position a plurality of plastic lenses on the holding frame, a presser frame is used, and the claw of the presser frame is engaged with the engaged portion of the holding frame to fix the plurality of plastic lenses. Is. By adopting such a structure, a lens device in which a plurality of plastic lenses are combined can be made inexpensive and can be easily and accurately positioned on the holding member.

  In the above-described aspect, particularly when positioning is performed by the tapered portion, the positioning accuracy between the plurality of plastic lenses can be determined by the respective tapered portions without using the holding frame so that the accuracy can be easily obtained. become. In addition, since a plurality of plastic lenses are used, the expansion due to the temperature characteristics is the same between the adjacent lenses, and there is no deviation due to the thermal expansion between the lenses. Further, by using a plastic lens, the cost can be reduced and the weight can be reduced as compared with the case of using a glass lens.

  Also, according to the structure in which a plurality of plastic lenses are mounted in the holding frame with the taper portions positioned with respect to each other, and fixed to the holding frame with a holding frame for fixing, heat caulking to fix the lens is not required Therefore, the equipment for that is no longer necessary. In addition, the assembly tact time is shortened, the assembly is facilitated, and the assembly can be performed only by hand. Further, since heat caulking is not performed, it is not necessary to apply heat stress to the plastic lens. Further, by removing the presser frame, the lens device can be easily disassembled and repaired. Alternatively, it can be disassembled and the plastic lens can be recovered and reused.

  According to the above main invention of the present application, it becomes possible to position the lenses adjacent to each other in the axial direction in the radial direction by fitting the tapered concave portions and the tapered convex portions to each other. Therefore, it is possible to perform positioning using the shape of the lens itself without requiring any positioning means.

  Another main invention of the present application is to position these lenses in the radial direction by engaging the stepped convex portions and the stepped concave portions formed on the lenses adjacent to each other and engaging the concave and convex portions. The lens device can be assembled. Here, since the positioning accuracy in the radial direction is determined by the fitting accuracy between the stepped convex portion and the stepped concave portion, the positioning accuracy can be easily controlled.

  In another invention of the present application, a plurality of lenses positioned in the radial direction by a tapered concave portion and a tapered convex portion are housed in a holding frame, and these lenses are pressed by a holding frame. By simply engaging the presser frame with the holding frame without heat-clamping the lenses positioned in the radial direction, the lens can be pressed and assembled easily.

  According to still another main invention of the present application, a plurality of lenses positioned in the radial direction by the stepped convex portion and the stepped concave portion are accommodated in the holding frame, and the plurality of lenses are pressed by the holding frame. Therefore, it becomes easy to fix and assemble the lens positioned by the stepped convex portion and the stepped concave portion, and it is possible to accurately position the plurality of lenses on the holding frame.

  The invention included in the present application will be described below with reference to the illustrated embodiments. This embodiment relates to an optical system used in a video camera, and includes a lens barrel 5 having a substantially cylindrical shape as shown in FIGS. The lens group 1, the image frame setting lens group 2, the correction lens group 3, and the focusing lens group 4 constituting the objective lens are arranged along the optical axis direction. In particular, the present embodiment relates to an improvement in the assembly structure of the movable image frame setting lens group 2 and the focusing lens group 4.

  FIG. 3 shows in principle the optical system of the imaging apparatus of the present embodiment. This embodiment relates to a lens apparatus provided with a video camera, and a lens called a zoom lens capable of image frame adjustment is used, and a plurality of lens groups 1, 2, 3, 4 are arranged. Is used as an image frame setting lens. The image frame setting lens group 2 is a lens group that can move in the optical axis direction within the lens barrel 5, and is driven by a servo motor 13a. The lens group 4 is a lens group for focus adjustment. The focus adjustment lens group 4 is also a lens group that can move in the optical axis direction within the lens barrel 5, and is controlled by a servo motor 13b or a stepping motor. Driven. Here, each of the servo motors 13a and 13b is composed of a linear motor, and a drive signal is supplied from the servo circuit 37 shown in FIG.

  The positions of the lens groups 2 and 4 driven by the servo motors 13a and 13b are magnetically detected by MR sensors 23 and 25 using MR elements, and this detection information is shown in the servo circuit 37 in FIG. So that you have feedback.

  An imaging element 31 is disposed on the surface on which the optical system is imaged by the lens device 10. The image sensor 31 converts the optical image into an electrical image signal. A CCD imager is used as the image sensor 31. The image pickup signal read from the image pickup element 31 is converted into a digital signal by the A / D converter 32 in FIG. 2 and then supplied to the image pickup signal processing circuit 33 to perform processing for making an appropriate video signal. The processed video signal is output from the imaging device. Or when this imaging device is a video camera provided with a video signal recording unit, the obtained video signal is recorded by the recording unit.

  Here, the imaging signal processing circuit 33 includes a detection circuit 34 that detects a predetermined component of the imaging signal, for example, a high frequency component of luminance, and controls the imaging operation of the imaging apparatus using the detection signal of the detection circuit 34. To a central control unit (CPU) 35. The central control unit 35 determines the focus state, that is, the focus state based on the level of the detection signal, and performs automatic focus control so that the determined focus state becomes the just focus state.

  In this focus control, the servo control process for supplying the target position information of the focus control lens group 4 from the central control unit 35 to the servo circuit 37 and driving the focus adjustment lens group 4 to the target position by the servo circuit 37 is performed. To generate a drive signal for the motor 13b, supply this drive signal to the servo motor 13b, and adjust the movable position of the focus adjustment lens group 4.

  The central control unit 35 is supplied with operation information of a zoom operation key (not shown). Based on the operation information of the zoom operation key, the target position information of the image frame setting lens 2 is converted into a servo circuit. 37, the servo circuit 37 performs servo control processing for driving the image frame setting lens group 2 to the target position to generate a drive signal for the motor 13a, and supplies the drive signal to the servo motor 13a. The movable position of the image frame setting lens group 2 is adjusted.

  In this case, the drive speed of the image frame setting lens group 2 by the servo motor 13a can be varied according to the operation state of the zoom operation key, and when driven at the highest speed, the wide end (that is, the focal length is the longest). The time required for the image frame setting lens group 2 to move from the short state to the telephoto end (that is, the state with the longest focal length) can be driven at a very high speed of less than 1 second.

  Even if the zoom lens 2 has the same focus position, the just focus state cannot be maintained unless the movable position of the focus adjustment lens group 4 is changed when the image frame (focal length) changes. The correspondence between the focal length and the position of the focus adjustment lens group 4 in the just-focus state is set in advance in the memory 36 connected to the central control unit 35. When the focal length changes, the central control unit 35 reads information stored in the memory 36, supplies a servo control signal for focus control to the servo circuit 37, and adjusts the movable position of the focus adjustment lens group 4. .

  In this case, the focus adjustment lens group 4 can be driven at a very high speed by the servo motor 13b. For example, when the image frame setting lens group 2 is moved at a high speed as described above, The process of correcting the movable position of the focus adjustment lens group 4 following the movement and maintaining the just focus state can be performed at high speed.

  Next, an example of a mechanism for moving the lens groups 2 and 4 in the optical axis direction will be described with reference to FIGS. FIG. 3 shows the internal structure of the lens device 10. A plurality of lens groups 1, 2, 3, 4 and an image sensor 31 are arranged along the optical axis, and the lens groups 1, 3 are fixed. The lens groups 2 and 4 are structured to be movable in the optical axis direction. In FIG. 3, the optical system including the lens groups 1 to 4 is shown in a simplified manner, and in actuality, each group is often composed of a plurality of lenses. Further, the position of the movable lens group is not limited to the example of FIG.

As a configuration for moving the lens groups 2 and 4, as shown in FIG. 4, two axes 11 and 12 are arranged vertically in almost parallel to the optical axis. The holding frames 45 and 19 of the lens groups 2 and 4 are supported. That is, the image frame setting lens group 2 is configured to be supported on the two shafts 11 and 12 by the shaft support portions 15 a and 15 b provided on the holding frame 45. A magnetic circuit 13 including a magnet and a yoke extending in the optical axis direction is disposed along the axis 11. As shown in FIG. 4, the coil 14 is arranged on the movable side so as to face the magnet, and when a drive signal is applied to the coil 14 from the servo circuit 37, a propulsive force in the optical axis direction (Lorentz) is applied by the voltage. Power). Here, by controlling the voltage value and its polarity by the servo circuit 37, a propulsive force having an appropriate direction and size can be obtained, and the lens group 2 moves at a desired direction and speed. Movable range of the lens unit 2 is shown as L ₁ in Figure 3.

  A rod-shaped magnet 22 magnetized in a predetermined pattern is attached to the holding frame 16 of the lens group 2, and a two-phase MR element 23 is used on the fixed side through a predetermined gap with the magnet 22. MR sensor 23 is arranged, and servo circuit 37 determines the movable position of lens group 2 from the output of MR sensor 23.

The configuration for moving the focus adjustment lens group 4 is the same as that shown in FIG. 3, and the shaft support portions 18a and 18b attached to the holding frame 19, as shown in FIG. The lens group 4 is configured to move when a drive signal is applied from the servo circuit 37 to the supported coil 17 facing the magnet of the magnetic circuit 13. Movable range of the lens group 4 is shown in FIG. 3 as L _2.

  A rod-shaped magnet 24 magnetized in a predetermined pattern is also attached to the holding frame 19 of the lens group 4, and MR using a two-phase MR element is provided on the fixed side via this magnet and a predetermined gap. A sensor 25 is arranged. Then, the servo circuit 37 determines the movable position of the lens group 4 from the output of the MR sensor 25.

  Next, processing when the movable positions of the image frame setting lens group 2 and the focus adjustment lens group 4 are changed by the imaging apparatus will be described. When changing the movable range, the target position information of the lens groups 2 and 4 is given from the central control unit 35 shown in FIG. 2 to the servo circuit 37, and basically the period of imaging with this imaging device. What is necessary is just to make it move to the target position with the period of one field (50 Hz or 60 Hz). Here, in the case of the imaging apparatus of the present embodiment, the target position obtained from the central control unit 35 is interpolated by calculation in the servo circuit 37, and the respective lens groups 2, 4 in a cycle of about 20 to 30 KHz. Thus, servo control is performed by applying a voltage to each of the motors 13a and 13b so that the difference between the target value of the interpolated period and the current position is eliminated.

  Next, an assembly structure of the lens groups 2 and 4 moved by the holding frames 45 and 19 of the lens device 10 will be described. Here, the configuration when used for the image frame setting lens group 2 will be described.

  As shown in FIGS. 5 and 6, the image frame setting lens group 2 includes three lenses 41, 42, and 43 from the front to the rear. These lenses are both made of epoxy plastic lenses. An opaque fixed diaphragm 44 having a ring shape is disposed between the lenses 41 and 42. The lenses 41 to 43 and the fixed diaphragm 44 are accommodated in the holding frame 45 and are fixed by being pressed by the pressing frame 46 from the rear side.

  FIGS. 7 and 8 show the structure of the front lens 41 arranged on the objective lens 1 side. The lens 41 has a positioning projection 49 on the top and another small positioning projection on the side. 50 is formed. The lens 41 has a tapered recess 51 formed on the back side thereof, and a ring-shaped protrusion 52 that extends concentrically with the tapered recess 51 in the circumferential direction.

  9 and 10 show the lens 42 disposed at the intermediate position. The lens 42 is provided with a positioning projection 55 at the top and a positioning projection 56 at the side. A tapered convex portion 57 is formed on the front side. The tapered convex portion 57 is aligned with the tapered concave portion 51 of the lens 41. A ring-shaped groove 58 is formed on the inner side concentrically with the tapered convex portion 57. The ring-shaped groove 58 is engaged with the ring-shaped protrusion 52 of the lens 41. Further, tapered concave portions 61 and 62 are formed concentrically on the rear surface of the lens 42.

  Next, the lens 43 disposed on the rear side and on the image pickup device 31 side will be described. The lens 43 includes a positioning projection 65 on the upper portion thereof as shown in FIGS. A positioning projection 66 is formed on the side of the lens 41. Tapered convex portions 67 and 68 are formed on the front side of the lens 43. These tapered convex portions 67 and 68 are aligned with the tapered concave portions 61 and 62 of the intermediate lens 42.

  Next, a holding frame 45 that holds the above-described three lenses 41, 42, and 43 in a state of overlapping as shown in FIG. 6 will be described with reference to FIGS. The main part of the holding frame 45 has a cylindrical shape, and a holding cylinder 71 that is slightly smaller in a concentric shape is integrally provided inside the holding frame 45 as shown in FIG. In the holding cylinder 71, notches 72 and 73 are formed at positions that are approximately 180 degrees apart from each other in the circumferential direction. In addition, a recess 74 is formed at a position that is approximately 90 degrees with respect to the notches 72 and 73.

  The holding frame 45 is provided with an engaging rib 75 at the bottom. As shown in FIGS. 16 and 17, the engaging rib 75 has a front surface on the tip side formed on an inclined surface 76. A recessed portion 77 that is lowered is formed on the terminal end side of the inclined surface 76. The holding frame 45 includes a guided cylinder 78. The guided cylinder 78 is for receiving the support shaft 11 (see FIGS. 3 and 4) of the lens device 10. In addition, an arm 79 is connected to the holding frame 45 at a position that is substantially 180 degrees shifted in the circumferential direction from the guided cylinder 78, and an insertion hole 80 is formed in the arm 79. The insertion hole 80 is for inserting the support shaft 12 shown in FIGS. 3 and 4.

  Next, a presser frame 46 for pressing the lenses 41, 42, 43 accommodated in the holding frame 45 will be described with reference to FIGS. The presser frame 46 is substantially cup-shaped, and three pawls 83 projecting outward in the radial direction are formed at positions 120 degrees apart from each other in the circumferential direction on the outer peripheral portion on the distal end side. Further, pressing protrusions 84 are formed at three positions in the circumferential direction on the bottom of the presser frame 46 and at positions shifted by 60 degrees from the claw 83 in the circumferential direction. Three slits 85 and 86 are formed in the wall portion on the back side of the presser frame 46 along the circumferential direction so that these pressing projections 84 have elasticity.

  Next, the assembling operation of the lens apparatus having the above configuration will be described. First, the three lenses 41, 42, 43 are positioned in the radial direction with respect to each other. In this positioning operation in the radial direction, the tapered concave portion 51 and the ring-shaped protrusion 52 of the lens 41 are engaged with the tapered convex portion 57 and the ring-shaped groove 58 of the second lens 42 to perform positioning. Next, the tapered concave portions 61 and 62 on the back side of the intermediate lens 42 are engaged with the tapered convex portions 67 and 68 of the rear lens 43 to perform positioning in the radial direction.

  Next, the positioning of the lenses 41, 42, 43 in the circumferential direction is performed by inserting the positioning protrusions 49, 55, 65 of the lenses 41, 42, 43 into the notches 72 of the holding frame 45. Positioning is performed by engaging other small positioning protrusions 50, 56, 66 in the recess 74 of the holding frame 45. As a result, the three lenses 41, 42, 43 are accommodated in the holding cylinder 71 of the holding frame 45 as shown in FIGS. 5 and 6 while being positioned in the radial direction and the circumferential direction, respectively.

  In such a state, the presser frame 46 shown in FIGS. 19 and 20 is fitted to the outer peripheral surface of the holding cylinder 71 of the holding frame 45 from the back side (see FIG. 6). Then, the claw 83 provided on the outer peripheral side of the presser frame 46 and at the distal end is pulled to the inclined surface 76 of the engaging rib 75 formed on the outermost peripheral side of the holding cylinder 71 of the holding frame 45 and at the innermost part. In this state, the presser frame 46 is rotated clockwise in FIG. 15 with respect to the holding frame 45. Then, the claw 83 of the presser frame 46 rises in the inclined surface 76 of the engagement rib 75 of the holding frame 45 and eventually falls into the recess 77, and the claw 83 and the engagement rib 75 are engaged with each other, as shown in FIG. become. This state is a state in which the three lenses 41, 42, 43 are stored in the holding frame 45 in a state where they are correctly positioned and are pressed by the presser frame 46.

  As described above, in the present embodiment, the lens device includes three plastic lenses 41, 42, and 43, and the material of these plastic lenses 41, 42, and 43 is made of an epoxy-based thermoplastic resin. Is done. Then, both the lenses 41 and 42 are relatively positioned by the tapered concave portion 51 of the lens 41 and the tapered convex portion 57 of the lens 42. Furthermore, the tapered concave portion 61 of the lens 42 and the tapered convex portion 67 of the lens 43 Are positioned relative to each other.

  In addition, it is preferable to mirror-finish the surfaces of the tapered concave portions 51 and 61 and the tapered convex portions 57 and 67 for positioning, and the taper angle is set to 45 degrees here, for example. The lenses 41, 42, and 43 have a backlash in the thickness direction, and are not positioned except for the tapered concave portion 51, the tapered convex portion 57, the tapered concave portion 61, and the tapered convex portion 67. Yes.

  Further, the three lenses 41, 42, and 43 are assembled in the order in the holding cylinder 71 of the holding frame 45, and finally the presser frame 46 is assembled in the holding frame 45. Here, by inserting the claw 83 of the presser frame 46 into the hole portion on the front side of the holding frame 45 and rotating the presser frame 46 with respect to the holding frame 45, the claw 83 is inclined by the engagement rib 75 of the holding frame 45. The vehicle is moved over the surface 76 and engaged with the recess 77 so as to be coupled by bayonet type engagement. At this time, the spring property generated by the slits 85, 86 of the presser frame 46 is utilized, and the back side of the rear lens 43 is pressed by the pressing projection 84, thereby the three lenses 41 against the holding frame 45. , 42 and 43 are held elastically.

  Therefore, according to such a lens device, the positional accuracy between the three plastic lenses 41, 42, and 43 is a tapered concave portion provided in each of these lenses 41, 42, and 43 without using the holding frame 45. 51, the taper-shaped convex part 57, the taper-shaped concave part 61, and the taper-shaped convex part 67 can determine, and positioning accuracy comes out easily. In addition, since a plurality of plastic lenses 41, 42, and 43 made of the same material are combined, the expansion due to the temperature characteristics is the same, and there is no deviation between the lenses 41, 42, and 43. Further, by using plastic as the material of these lenses 41, 42 and 43, cost can be reduced and weight reduction can be achieved at the same time.

  In addition, as shown in FIGS. 5 and 6, such a lens device has a configuration in which three lenses 41 to 43 are accommodated in a holding frame 45, and the presser frame 46 is fitted from the back side and rotated. Well, the assembly becomes very easy, and it can be easily assembled manually, so that not only an automatic assembly facility is required but also a heat caulking facility is not necessary. Further, since heat caulking is not required, it is not necessary to apply heat stress to the plastic lenses 41, 42, 43. Further, the lens device can be easily disassembled by rotating the presser frame 46 in the direction opposite to the assembly direction and pulling it out to the back side. Therefore, it is possible to easily repair, and in some cases, the plastic lenses 41, 42, 43 can be removed and reused.

  Next, another embodiment will be described with reference to FIG. In this embodiment, the three lenses 41, 42, 43 are positioned in the radial direction instead of the tapered concave portion 51, the tapered convex portion 57, the tapered concave portion 61, and the tapered convex portion 67. Positioning in the radial direction is performed using positioning step portions 41, 42, and 43 extending in the circumferential direction.

  A concave positioning step 91 is formed on the back side of the lens 41, and a convex positioning step 92 that is engaged with the positioning step 91 is formed on the front side of the lens 42. . A concave positioning step 93 is formed on the back side of the lens 42. On the other hand, a convex positioning step 94 is formed on the front side of the lens 43.

  Therefore, the concave positioning step 91 on the back side of the lens 41 and the convex positioning step 92 on the front side of the lens 42 are engaged with each other to perform positioning between the lenses 41 and 42. The concave positioning step 93 on the back side of the lens 42 is engaged with the convex positioning step 94 on the front side of the lens 43. As a result, the three lenses 41, 42, 43 are positioned in the radial direction. The positioning of these lenses 41 to 43 in the circumferential direction and the fixing structure by the holding frame 46 with respect to the holding frame 45 are the same as in the above embodiment.

  Therefore, according to such a configuration, it becomes possible to position the three lenses 41 to 43 in the radial direction using the four positioning step portions 91 to 94. Here, these positioning step portions 91 to 94 are both step portions formed in the circumferential direction of the lenses 41 to 43. The positioning accuracy in the radial direction is determined by the fitting accuracy. In other words, the positioning accuracy can be arbitrarily adjusted using the fitting accuracy.

  Although the invention included in the present application has been described with the illustrated embodiment, the invention included in the present application is not limited to the above-described embodiment, and various modifications are possible within the scope of the technical idea of the invention included in the present application. Is possible. For example, the above embodiment is applied to a lens for setting an image frame in a lens device of a video camera. However, the present invention is a lens device of other various optical devices such as a digital still camera. Also widely applicable.

  The present invention can be widely applied to a lens apparatus in which a plurality of lenses are combined and held in a holding frame, such as a video camera or a digital still camera.

It is an external appearance perspective view of the lens barrel of a video camera.

It is a block diagram of a control system of movement control of a movable lens.

It is a principle figure which shows the moving mechanism of a movable lens.

It is a side view of the movable mechanism of a lens.

It is a disassembled perspective view of a lens apparatus.

It is an assembly longitudinal cross-sectional view of a lens apparatus.

It is a front view of a front lens.

It is a longitudinal cross-sectional view of the lens.

It is a front view of an intermediate lens.

It is a longitudinal cross-sectional view of the lens.

It is a front view of a rear lens.

It is a longitudinal cross-sectional view of the lens.

It is a front view of a holding frame.

It is a bottom view of a holding frame.

It is a rear view of a holding frame.

It is AA sectional drawing in FIG.

It is BB sectional drawing in FIG.

It is CC sectional drawing in FIG.

It is a front view of a presser frame.

It is the longitudinal cross-sectional view (DD sectional drawing in FIG. 19) and side view of the presser frame.

It is assembly sectional drawing of the lens apparatus of a modification.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Lens group (objective lens), 2 ... Lens group (for image frame setting), 3 ... Lens group (for correction), 4 ... Lens group (for focus), 5 ... Lens barrel, 10 ... Lens unit 11, 12, Support shaft, 13 Magnetic circuit, 13a, 13b Servo motor, 14 Movable coil, 15a, 15b Shaft support, 16 Holding frame, 17 Moving coil, 18a, 18b ... Shaft support, 19 ... Holding frame, 22 ... Magnet, 23 ... MR sensor (image frame setting), 24 ... Magnet, 25 ... MR sensor (for focus), 31 ...... Image sensor, 32 A / D converter, 33 Imaging signal processing circuit, 34 Detection circuit, 35 Central control unit (CPU), 36 Memory, 37 Servo circuit, 41 ... 43 Lens, 44 Fixed aperture, 45 Holding frame 46 ... Presser frame, 49, 50 ... Positioning protrusion, 51 ... Tapered recess, 52 ... Ring protrusion, 55, 56 ... Positioning protrusion, 57 ... Tapered protrusion, 58 Ring groove, 61, 62 Tapered recess, 65, 66 Positioning projection, 67, 68 Tapered projection, 71 Holding cylinder, 72, 73 Notch, 74 ·················································· 75 ·························································································· Projection, 85, 86 ... Slit, 91 ... Positioning step (concave), 92 ... Positioning step (convex), 93 ... Positioning step (concave), 94 ... Positioning step Part (convex)

Claims (14)

In a lens device that is assembled to overlap a plurality of lenses,
A tapered concave portion is formed in one lens adjacent to each other in the axial direction, a tapered convex portion is formed in the other adjacent lens, and the tapered concave portion and the tapered convex portion are fitted to each other in a concave-convex manner. A lens device that performs positioning in a radial direction.   2. The lens device according to claim 1, wherein lenses which are adjacent to each other and perform positioning in a radial direction by the tapered concave portion and the tapered convex portion are plastic lenses.   The lens device according to claim 1, wherein a taper angle of the tapered concave portion and a taper angle of the tapered convex portion are substantially equal to each other.   The lens apparatus according to claim 1, wherein a fixed diaphragm is sandwiched and attached between adjacent lenses. In a lens device assembled by overlapping a plurality of lenses,
A stepped concave portion is formed in one lens adjacent to each other in the axial direction, a stepped convex portion is formed in the other adjacent lens, and the stepped concave portion and the stepped convex portion are fitted to each other in a concave-convex manner. A lens device that performs positioning in a radial direction.   6. The lens device according to claim 5, wherein the lenses that are adjacent to each other and that perform positioning in the radial direction by the step-shaped concave portion and the step-shaped convex portion are plastic lenses.   The lens apparatus according to claim 5, wherein a diameter of the stepped concave portion and a diameter of the stepped convex portion are substantially equal to each other.   The lens apparatus according to claim 5, wherein a fixed diaphragm is attached between the adjacent lenses. In a lens device that is assembled to overlap a plurality of lenses,
A tapered concave portion is formed in one lens adjacent to each other in the axial direction, a tapered convex portion is formed in the other adjacent lens, and the tapered concave portion and the tapered convex portion are fitted to each other in a concave-convex manner. Perform radial positioning,
A lens device, wherein the plurality of lenses are housed in a holding frame, and the plurality of lenses are pressed by a pressing frame.   The lens device according to claim 9, wherein a claw provided on one of the presser frame and the holding frame is engaged with an engagement hole provided on the other to press the lens device.   The lens device according to claim 10, wherein the engagement between the claw and the engagement hole is a bayonet type engagement. In a lens device that is assembled to overlap a plurality of lenses,
A stepped concave portion is formed in one lens adjacent to each other in the axial direction, a stepped convex portion is formed in the other adjacent lens, and the stepped concave portion and the stepped convex portion are fitted to each other in a concave-convex manner. Perform radial positioning,
A lens device, wherein the plurality of lenses are housed in a holding frame, and the plurality of lenses are pressed by a pressing frame.   The lens device according to claim 12, wherein a claw provided on one of the presser frame and the holding frame is engaged with an engagement hole provided on the other to press the lens device. 14. The lens device according to claim 13, wherein the engagement between the claw and the engagement hole is a bayonet type engagement.

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