JP2008134569A - Lens barrel and projector device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the flexibility of arrangement of a member arranged near a lens barrel 6 by making the dimension of a cam barrel along an optical axis direction smaller. <P>SOLUTION: The first cam follower 46 of a first lens group 21 and the second cam follower 56 of a second lens group 22 are engaged with a first cam groove 71 and a second cam barrel 72 which are formed in the cam barrel 25. The first lens group 21 and the second lens group 22 are moved accompanying rotation of the cam barrel 25. The first cam groove 71 and the second cam barrel 72 are arranged side by side in a peripheral direction. The dimension D of the cam barrel 25 in a direction along an optical axis O can be made smaller than that in such a configuration that these cam grooves 71 and 72 are arranged along the direction of the optical axis O. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to, for example, a lens barrel having a cam structure that moves a plurality of lens groups along an optical axis direction, and a projector apparatus including the lens barrel.

  Conventionally, it has an illumination optical system composed of a light source, a liquid crystal display element that is a light modulation means, and a lens barrel that is a projection optical system. The light emitted from the light source is modulated by the liquid crystal display element, and the light is modulated. A projector device that projects a projected image on a screen or the like using a lens barrel is known. The lens barrel includes a plurality of lens groups each holding a lens in a lens frame, and zoom and focus adjustments are performed by moving these lens groups along the optical axis direction.

For the movement of the lens group, a cam cylinder is provided coaxially with each lens frame, a cam follower, which is a pin protruding from each lens frame, is engaged with a cam groove provided in the cam cylinder, and the cam cylinder is rotated. By moving, each lens group is moved back and forth along the optical axis direction (see, for example, Patent Document 1).
JP 2004-347646 A (FIGS. 1-3)

  However, in the above-described conventional configuration, for example, in the case of the three-group configuration, the cam follower that projects from each lens frame of the three lens groups arranged along the optical axis direction is driven. Since three rows of cam grooves are formed along the direction, and the dimension along the optical axis direction of the cam barrel increases, there is a problem that the arrangement of the members arranged close to the lens barrel is limited. is doing.

  SUMMARY An advantage of some aspects of the invention is that it provides a lens barrel and a projector device that can reduce the size of a cam barrel.

  The lens barrel according to claim 1 includes a first lens frame provided with a first lens, a first lens holding portion that holds the first lens, and a first cam follower, along the optical axis. A second lens frame provided with a first lens group supported so as to be movable back and forth, a second lens, a second lens holding portion for holding the second lens, and a second cam follower; A second lens group supported movably back and forth along the optical axis, a first cam groove engaged with the first cam follower, and a second cam groove engaged with the second cam follower. The first cam groove and the second cam groove are at least partially located on the same plane orthogonal to the optical axis, and are supported so as to be rotatable about the optical axis. A cylinder.

  In this configuration, by rotating the cam cylinder, the first lens group and the second lens group move back and forth, and adjustments such as zoom or focus are performed. Since the first cam groove and the second cam groove are at least partially located on the same plane orthogonal to the optical axis, that is, on the same circumference, the size of the cam cylinder along the optical axis direction is reduced. It becomes possible. Therefore, the degree of freedom of arrangement of members arranged close to the lens barrel is improved.

  The lens barrel according to claim 2 is the lens barrel according to claim 1, wherein the first lens frame is a first frame main body having a first lens holding portion provided on the inner peripheral side. A plurality of first support pieces projecting from the first frame main body along the optical axis direction, and first cam followers projecting from the first support pieces to the outer peripheral side, respectively. The second lens frame has a cylindrical second frame main body provided with a second lens holding portion on the inner peripheral side, and a plurality of second lens frames along the optical axis direction from the second frame main body. A second support piece projectingly provided; and a second cam follower projecting outwardly from each of the second support pieces, the first support piece and the second support piece. The portions are alternately arranged in the circumferential direction along the inside of the cam cylinder.

  In this configuration, the first cam groove and the second cam groove are located on the same plane, at least part of which is perpendicular to the optical axis, and the dimension along the optical axis direction of the cam cylinder is reduced. The configuration is easily realized.

  The lens barrel according to claim 3 is the lens barrel according to claim 2, and includes a cylindrical guide tube provided with a guide groove along the optical axis direction, and the first lens frame and the second lens frame. The first cam follower and the second cam follower are engaged with the guide groove, and the first frame main body and the second frame main body are moved back and forth along the optical axis direction on the inner peripheral side of the guide tube. The cam cylinder engages the first cam follower penetrating the guide groove with the first cam groove, and the second cam follower penetrating the guide groove is the second cam groove. And is fitted to the outer peripheral side of the guide tube so as to be rotatable.

  And in this structure, the structure which moves a 1st lens group and a 2nd lens group back and forth along an optical axis direction is easily implement | achieved by rotating a cam cylinder.

  The projector device according to claim 4 projects a light source, a light modulation unit that modulates light emitted from the light source, and a light that is modulated by the light modulation unit. And a lens barrel.

  In this configuration, since the lens barrel according to any one of claims 1 to 3 is provided, a member such as a light modulating unit can be disposed close to the lens barrel without interfering with the lens barrel. The degree of freedom of arrangement of members is high and miniaturization becomes easy.

  According to the present invention, since the first cam groove and the second cam groove of the lens barrel are located at least partially on the same plane orthogonal to the optical axis, that is, on the same circumference, The dimension along the optical axis direction can be easily reduced. Therefore, the degree of freedom of arrangement of the members arranged close to the lens barrel is improved, and the projector device using the lens barrel can be easily downsized.

  Hereinafter, an embodiment of a lens barrel and a projector apparatus according to the present invention will be described with reference to the drawings.

  In FIG. 8, reference numeral 1 denotes a projector device. The projector device 1 is a liquid crystal projector, and is housed in a light source 2, an internal housing 3 into which illumination light emitted from the light source 2 is incident, and the internal housing 3. Optical elements (not shown), light modulation means 4 including three transmissive LCD panels 4r, 4g, and 4b that are liquid crystal display elements, a dichroic cross prism 5 as a composite optical system, and a lens barrel for a projector device A lens barrel 6 is provided. The light source 2 and the inner housing 3 are covered with a horizontally long box-shaped exterior cover 7 as an exterior body. In the exterior cover 7, a fan, a control circuit, an operation unit, a display unit, a power supply device and the like (not shown) are arranged.

  Hereinafter, with respect to the optical axis O of the illumination light directed from the light source 2 to the screen, the screen side is the front side, the light source 2 side is the rear side, and the direction perpendicular to the optical axis when viewed from the light source 2 side is the vertical direction, that is, the vertical direction. , And the left-right direction, that is, the horizontal direction.

  The light source 2 includes an incandescent lamp such as a halogen lamp (not shown) or a discharge lamp such as a metal halide lamp, and a parabolic surface that reflects the light emitted from the discharge lamp around the discharge lamp. A reflector having a mirror surface is disposed. Therefore, light emitted from the discharge lamp is reflected from the light source 2 by the reflector and enters the internal housing 3. The internal housing 3 is formed in a box shape, and various optical elements (not shown) such as various filters and various lenses are formed inside the internal housing 3 and are arranged and held at predetermined positions. . The various optical elements, for example, separate light emitted from the light source 2 into three color lights of R (red), G (green), and B (blue), and the respective color lights are divided into LCD panels 4r and 4g. , 4b respectively. Then, each LCD panel 4r, 4g, 4b modulates each color light according to a predetermined video signal and transmits it to the dichroic cross prism 5. Further, the dichroic cross prism 5 combines the three colors of color light modulated in accordance with a predetermined video signal through the LCD panels 4r, 4g, and 4b into the combined light and makes it incident on the lens barrel 6. These are formed in a quadrangular shape in plan view, and are disposed in the recesses 11 provided in the housing 3. The dichroic cross prism 5 has three side surfaces that are incident surfaces facing the LCD panels 4r, 4g, and 4b, and a front side surface that is an emitting surface is facing the lens barrel 6.

  The lens barrel 6 is a projection lens that projects the light synthesized by the dichroic cross prism 5 onto a screen (not shown) or the like. The lens barrel 6 is embedded in an exterior cover 7 and has an inner casing 3 and a surrounding part around the rear side. Members such as the light modulation means 4 are supported in a state of being arranged close to each other. As shown in FIGS. 1 to 3, the lens barrel 6 includes a third lens group 20 as a first moving group and a first lens group 21 as a second moving group in order from the front side. , And a second lens group 22 that is a third moving group, and a guide cylinder 24 and a cam cylinder 25 that are coaxially combined with the lens groups 20, 21, and 22, and these members. A mounting base 27 and a drive mechanism 28 are attached to the rear side portion.

  That is, the first to fifth lenses L1 to L5 included in the third lens group 20, the sixth and seventh lenses L6 and L7 constituting the first lens included in the first lens group 21, and the second lens group. The eighth to eleventh lenses L8 to L11 constituting the second lens included in 22 have a central axis along the optical axis O.

  The third lens group 20 moves back and forth in order to adjust the focus (focus). As shown in FIGS. 1 to 3, for example, the third lens group 20 is formed in a substantially cylindrical shape made of synthetic resin such as polycarbonate. And a third focus tube 32 which is attached to the outer peripheral side of the third frame body 31 and is formed of a synthetic resin such as polycarbonate and has a substantially cylindrical shape. ing. The third frame main body 31 has a stepwise shape with a diameter increasing toward the front side, and first to fifth lens holding portions 31a1 for holding the first to fifth lenses L1 to L5 on the inner peripheral portion. ~ 31a5 is formed. The fourth lens holding portion 31a4 and the fifth lens holding portion 31a5 have substantially the same inner diameter, the third lens holding portion 31a3 has a larger inner diameter than the fourth lens holding portion 31a4, and the second lens holding portion 31a2 The first lens holding portion 31a1 has a larger inner diameter than the third lens holding portion 31a3, the first lens holding portion 31a1 has a larger inner diameter than the second lens holding portion 31a2, and the first to fifth lenses L1 to L1 held by these lens holding portions 31a1 to 31a5. The same relationship applies to the outer dimensions of L5. In this embodiment, the first lens L1 is a meniscus lens having a convex surface facing the front side, the second lens L2 is a biconvex lens, and the third lens L3 is a meniscus lens having a convex surface facing the front side, The fourth lens L4 is a biconcave lens, and the fifth lens L5 is a biconvex lens. The third focus tube 32 is engaged with the third frame body 31 so as to cover the outer periphery of the third frame body 31 and is fixed by a screw 34 as a fixture. ing. A rack portion 35 is formed along the circumferential direction on the rear side portion of the outer peripheral surface of the third focus tube 32.

  The first lens group 21 moves back and forth in order to adjust the zoom. The first lens group 21 includes a first lens frame 41 formed of a synthetic resin such as polycarbonate, for example. A first frame main body portion 42 having a substantially cylindrical shape and a first support piece portion 43 protruding from the front side of the first frame main body portion 42 are integrally formed. Then, on the inner peripheral side of the first frame main body 42, sixth and seventh lens holding portions 42a6 and 42a7 constituting the first lens holding portion for holding the sixth and seventh lenses L6 and L7 are formed. Has been. The inner diameter dimension of the sixth lens holding part 42a6 is larger than that of the seventh lens holding part 42a7, and the same relationship is applied to the outer dimensions of the sixth and seventh lenses L6, L7 held by these lens holding parts 42a6, 42a7. It has become. In this embodiment, the sixth lens L6 is a biconvex lens, and the seventh lens L7 is a meniscus lens having a convex surface facing the rear side. Further, the outer peripheral portion of the first frame main body portion 42 is formed such that the outer dimension of the front side portion is larger than the outer dimension of the rear side portion via an inclined step portion 42b. Further, from the rear end portion of the first frame main body portion 42, there are alternately three pin portions 42c whose front end portion projects rearward and a cylindrical portion 42d whose front end portion opens rearward. Projecting each one, a ring-shaped member 44 can be fixed.

  And the 1st support piece part 43 makes | forms the cross-section circular arc shape in the space | interval of the substantially equal angle in the circumferential direction from several places of the front-end | tip part of the 1st frame main-body part 42, and three places in this Embodiment. Projected. The outer dimension of the outer peripheral surface of the virtual cylinder formed by the outer peripheral surface of the first support piece 43 is formed larger than the outer dimension of the first frame main body 42. Furthermore, from the outer peripheral surface of each 1st support piece part 43, the 1st cam follower 46 which is a pin is integrally protrudingly provided toward the outer peripheral side, respectively. Each first cam follower 46 has a substantially cylindrical shape, and the outer peripheral side, that is, the distal end side has an inclined surface with a smaller outer dimension.

  The second lens group 22 moves back and forth in order to adjust the zoom. The second lens group 22 includes a second lens frame 51 formed of a synthetic resin such as polycarbonate. The second lens frame 51 The second frame body 52 having a substantially cylindrical shape and the second support piece 53 protruding from the front side of the second frame body 52 are integrally formed. The inner peripheral side of the rear side portion of the second frame main body 52 has a second lens holding that holds the eighth to eleventh lenses L8 to L11 in a stepped manner toward the rear side. The 8th thru | or 11th lens holding | maintenance part 52a8-52a11 which comprises a part is formed. The eighth lens holding portion 52a8 and the ninth lens holding portion 52a9 have substantially the same inner diameter, and the inner diameter of the tenth lens holding portion 52a10 is larger than that of the ninth lens holding portion 52a9. The inner diameter dimension of the eleventh lens holding part 52a11 is large, and the outer dimensions of the eighth to eleventh lenses L8 to L11 held by these lens holding parts 52a8 to 52a11 have the same relationship. In this embodiment, the eighth lens L8 is a meniscus lens having a convex surface on the rear side, the ninth lens L9 is a biconcave lens, and the tenth lens L10 is a meniscus lens having a convex surface on the rear side. The eleventh lens L11 is a biconvex lens.

  Further, the second frame main body portion 52 of the second lens frame 51 is provided with a cylindrical storage cylinder portion 54 that is positioned in front of the lens holding portions 52a8 to 52a11. The inner diameter dimension of the storage cylinder portion 54 is larger than the inner diameter dimension of the lens holding portions 52a8 to 52a11, and the first frame body portion 42 of the first lens frame 41 can be accommodated inside. Further, the storage cylinder part 54 is formed such that the inner dimension of the front side part is larger than the inner dimension of the rear side part via an inclined step part 54b according to the shape of the first frame main body part 42. .

  In addition, the second support piece 53 has the same shape as the first support piece 43, and in the circumferential direction from a plurality of locations at the tip of the second frame body 52, in this embodiment, three locations. Protrusions having a circular arc shape are provided at substantially equal angular intervals. Furthermore, from the outer peripheral surface of each second support piece 53, a second cam follower 56, which is a pin, protrudes integrally from the outer peripheral surface. Each of the second cam followers 56 has a substantially cylindrical shape, and an outer peripheral side, that is, a distal end side is an inclined surface having a smaller outer dimension.

  The outer dimensions of the outer circumference of the virtual cylinder constituted by the outer circumference of the second support piece 53 are the outer circumference of the virtual cylinder constituted by the outer circumference of the first support piece 43. It is formed with the same external dimensions as. That is, as shown in FIG. 5, the first support piece 43 in a state where the first lens frame 41 and the second lens frame 51 are combined and the first frame main body 42 is housed in the housing cylinder 54. And the second support piece portions 53 are alternately arranged to form a virtual cylinder. Furthermore, in this state, the first cam follower 46 protruding from each first support piece 43 of the first lens frame 41 and the second support piece 53 of the second lens frame 51 protrude from each first support piece 53. The provided second cam followers 56 are arranged on a circumference centered on a certain point on the optical axis O at substantially equal intervals, that is, at intervals of 60 degrees. In the state where the first lens frame 41 and the second lens frame 51 are combined, a slight gap is set between the first support piece portion 43 and the second support piece portion 53 which are adjacent to each other. And are movable in the circumferential direction.

  The guide tube 24 can also be called a straight guide tube, and is formed of, for example, a synthetic resin such as polycarbonate, and has a substantially cylindrical guide tube body 61 and a front side of the guide tube body 61. A support portion 62 having a substantially cylindrical shape is integrally formed. Guide grooves 64, which are linear slits, are formed at six locations along the front-rear direction, that is, along the optical axis O, on the front side portion of the guide tube main body 61. Further, the rear side portion of the guide tube main body portion 61 is formed with an inner diameter dimension smaller than that of the front side portion via an inclined step portion 61a. The support 62 is larger than the guide tube main body 61 in both the inner diameter and the outer diameter, and is continuous to the guide tube main body 61 through the vertical wall portion 65. Further, the front end portion of each guide groove 64 is opened in the wall portion 65. Further, on the outer peripheral surface of the guide tube main body 61, a cam tube guide portion 61b having a rib shape along the circumferential direction is intermittently projected from the front end portion, that is, in the vicinity of the support portion 62. ing. Further, on the outer peripheral portion of the support portion 62, a spiral support protrusion (not shown) that protrudes toward the outer peripheral side and rotatably supports the third lens group 20 is provided.

  As shown in FIG. 6, the guide tube 24 has a first lens group 21 and a second lens group 22, that is, a first lens frame 41 combined with each other inside the guide tube body 61. The second lens frame 51 can be stored. Then, in a state in which the first lens frame 41 and the second lens frame 51 are housed, the cam followers 46 and 56 of the lens frames 41 and 51 are respectively inserted into the guide grooves 64 and are slidable in this embodiment. The first lens frame 41 and the second lens frame 51 are guided so as to be linearly movable back and forth. Further, as shown in FIG. 3, a third lens group 20 is rotatably attached to the front side portion of the guide tube 24.

  The cam cylinder 25 is formed of a synthetic resin such as polycarbonate, for example, and is formed in a cylindrical shape having a small dimension D along the front-rear direction, that is, along the optical axis O. As shown in FIG. 4, a front groove portion 70 is formed in the inner peripheral surface of the cam cylinder 25 so as to be thinly formed along the front end portion, and is continuous with the front groove portion 26. Corresponding to the cam followers 46 and 56 of the lens frames 41 and 51, the first cam grooves 71 and the second cam grooves 72 are alternately positioned in the circumferential direction at three locations, that is, a total of six The cam grooves 71 and 72 are formed so as to be thinly recessed at intervals of 60 degrees on the same circumference. That is, the first cam groove 71 and the second cam groove 72 have substantially the same shape and are formed so as to be mostly located on the same circumference with the optical axis O as the center. The first cam groove 71 and the second cam groove 72 are continuous with the front groove portion 70 and extend along the direction along the optical axis O, and the introduction groove portions 71a and 72a. A first cam groove portion 71b and a second cam groove portion 72b which are continuous with the rear end portion and are inclined by a predetermined angle with respect to the direction along the optical axis O are provided. In the present embodiment, the first cam groove 71 and the second cam groove 72 have substantially the same shape, but the length dimension of the second cam groove 72 is slightly larger than that of the first cam groove 71. Largely formed. That is, the shapes of the introduction groove portions 71a and 72a are the same, and the positions of the front end portions of the first cam groove portion 71b and the second cam groove portion 72b are the same, but the position of the rear end portion is the first cam groove portion. The second cam groove 72b protrudes slightly rearward than 71b.

  Further, the cam tube 25 is provided with an engaging portion 74 which is located at the front end portion on the inner peripheral side and has a rib shape along the circumferential direction, and protrudes intermittently on the inner peripheral side. Further, a rack portion 75 is formed along a part of the rear end portion on the outer peripheral portion of the cam tube 25, and a pair of restricting portions 76 for restricting the rotation range of the cam tube 25 are provided projectingly. ing.

  As shown in FIG. 7, the cam cylinder 25 is fitted to the outer peripheral portion of the guide cylinder main body 61 of the guide cylinder 24 and is rotatably supported. In this state, the engaging portion 74 engages with the cam tube guide portion 61b and is prevented from coming off and positioned in the front-rear direction, and the front end portion of the first cam follower 46 passing through the guide groove 64 of the guide tube 24 The distal ends of the two cam followers 56 are slidably engaged with the first cam groove 71 and the second cam groove 72, respectively.

  The mounting base 27 is formed of a synthetic resin such as polycarbonate, for example, and has an annular guide tube mounting portion 81 fitted to the rear end portion of the guide tube 24, and a vertical centered on the guide tube mounting portion 81. Triangular plate-like substrate portion 82 obtained by cutting off one lower corner portion of the rectangular plate-like member, and a drive mechanism protruding forward from the other lower corner portion of the substrate portion 82 The mounting portion 84 is integrally formed. The guide tube mounting portion 81 is formed with four through holes 81a into which screws, not shown, for fixing to the guide tube 24 are inserted. The board portion 82 is formed with three attachment holes 82a into which screws, which are fixing tools for fixing to the internal housing 3, are inserted. Further, the drive mechanism 28 is attached to the drive mechanism attachment portion 84 by screws or the like which are not shown.

  As shown in FIG. 3, the drive mechanism 28 includes, for example, a mounting base 91 formed of a synthetic resin such as polycarbonate, a focus driving mechanism 92 attached to the mounting base 91, and a mounting base 91. And a zoom drive mechanism (not shown) attached to the camera. The focus driving mechanism 92 includes a gear mechanism portion 92a, an electric motor 92b connected to the rear portion of the gear mechanism portion 92a, and a pinion 92c connected to the front side of the gear mechanism portion 92a. The pinion 92c is held at a predetermined position by a spring 92e attached to the shaft portion 92d and meshes with the rack portion 35 of the third lens group 20. On the other hand, the zoom drive mechanism is provided with a pinion that meshes with the motor, the gear mechanism portion, and the rack portion 75 of the cam cylinder 25, as in the focus drive mechanism 92, although not shown.

  Next, the operation of this embodiment will be described.

  Illumination light emitted from the light source 2 enters the internal housing 3 and is guided to various optical elements in the housing 3 to be separated into R (red), G (green), and B (blue) color lights. Then, these color lights are incident on the LCD panels 4r, 4g, 4b and modulated. The modulated color light enters the dichroic cross prism 5 from three directions, is color-combined by the dichroic cross prism 5, and enters the lens barrel 6.

  Then, the light incident on the lens barrel 6 sequentially passes from the eleventh lens L11 to the first lens L1, and is projected on the screen as a projected image.

  Here, when the motor 92b of the focus driving mechanism 92 is driven, the rotation of the motor 92b is transmitted to the pinion 92c via the gear mechanism 92a, and the rack portion 35 is driven by the rotation of the pinion 92c, so that the third The lens group 20 is rotated. Then, the third lens group 20 supported by the spiral support protrusion moves back and forth relative to the guide tube 24, that is, the first to fifth lenses L1 to L5 follow the optical axis O. As a result, the focal point of the projected image is adjusted.

  When the motor of the zoom drive mechanism is driven, the rotation of the motor is transmitted to the pinion via the gear mechanism, and the rack portion 75 is driven by the rotation of the pinion to rotate the cam cylinder 25. Then, the first and second cam grooves 71 and 72 of the cam cylinder 25 move, and the first cam follower 46 and the second cam follower 56 engaged with the first and second cam grooves 71 and 72 are Then, it is guided in the guide groove 64 and driven linearly back and forth. That is, the sixth and seventh lenses L6 and L7 of the first lens group 21 and the eighth to eleventh lenses L8 to L11 of the second lens group 22 are along the optical axis O with respect to the guide tube 24. The size of the projected image is adjusted by moving back and forth relatively, that is, by moving to the positions defined by the shapes of the first and second cam grooves 71 and 72, respectively.

  According to the present embodiment, the cam followers 46 and 56 projecting from the lens frames 41 and 51 of the plurality of lens groups 21 and 22, respectively, with respect to the cam structure of the moving group of the lens barrel 6 of the projector device 1, A configuration in which the plurality of lens groups 21 and 22 are moved back and forth along the optical axis O as the cam barrel 25 rotates by engaging with the cam grooves 71 and 72 of the cam barrel 25 is described. , 72 are positioned at least partially on the same plane orthogonal to the optical axis O, that is, on the same circumference, in the present embodiment, the first cam groove 71 and the second cam groove 72 have substantially the same shape. Since the cam grooves 71 and 72 are arranged along the direction of the optical axis O, the dimension D in the direction along the optical axis O of the cam cylinder 25 can be reduced.

  Therefore, a member disposed in the vicinity of the lens barrel 6, in particular, a member disposed in the vicinity of the rear side portion of the lens barrel 6 shown by an arrow A in FIG. 3 does not interfere with the cam barrel 25, The degree of freedom of arrangement of members such as internal structures is improved, and the projector device 1 can be easily downsized.

  Further, the configuration in which the plurality of cam grooves 71 and 72 are arranged side by side in the circumferential direction is such that the first frame body portion 42 of the first lens frame 41 is arranged inside the second frame body portion 52 of the second lens frame 51. And supporting pieces 43 and 53 projecting from the second frame main body 52 and the first frame main body 42 are alternately arranged in the circumferential direction. This can be easily realized by projecting cam followers 46, 56 from 43, 53. In other words, the first cam follower 46 of the first lens frame 41 of the front moving group is cut out, and the second cam follower 56 of the second lens frame 51 of the rear moving group is cut out in this cut-out portion. By arranging these, it is possible to easily realize a configuration in which the plurality of cam grooves 71 and 72 are arranged side by side in the circumferential direction.

  In the above embodiment, the configuration in which the two lens groups 21 and 22 are moved by the cam cylinder 25 has been described. However, the present invention is not limited to this configuration, and three or more lens groups can be moved. In this case, the dimension along the circumferential direction of the support piece projecting from each lens group can be reduced and arranged adjacent to each other.

  The plurality of cam grooves 71 and 72 have substantially the same shape as each other. However, the present invention is not limited to this configuration, and the inclination angles of the cam grooves 71 and 72 are set such that the plurality of lens groups 21 and 22 move in the opposite direction. You can also

  The first cam follower 46 and the second cam follower 56 have different pin diameters, that is, outer diameters, and the guide grooves 64 and the cam grooves 71 and 72 have different widths corresponding to the cam followers 46 and 56, respectively. This prevents misassembly during assembly and improves workability during assembly.

  Moreover, although each said member was formed, for example with polycarbonate, it is not restricted to this structure, It can also comprise combining synthetic resins, such as a polypropylene, metals, such as aluminum, or a metal and resin.

  Further, the projector apparatus 1 is not limited to the liquid crystal projector provided with one lens barrel 6, and may be configured to use a reflection type device as the light modulation means, or for each of the three light modulation means. A configuration including the lens barrel 6 may also be employed.

  Further, the cam cylinder 25 can be driven manually, in addition to being driven by a motor.

  The present invention can be applied to a projector device such as a liquid crystal projector.

It is a partial exploded perspective view showing one embodiment of a lens barrel of the present invention. It is explanatory drawing of the cross section of a lens barrel same as the above, The upper half is a wide angle state, and the lower half is a telephoto state. It is a one part perspective view of a lens-barrel same as the above. It is explanatory drawing of the inner surface which developed the cam cylinder of a lens-barrel same as the above. It is explanatory drawing which shows the assembly process of a lens-barrel same as the above. It is explanatory drawing which shows the assembly process of a lens-barrel same as the above. It is explanatory drawing which shows the assembly process of a lens-barrel same as the above. It is explanatory drawing of the projector apparatus provided with the lens-barrel same as the above.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Projector apparatus 2 Light source 4 Light modulation means 6 Lens barrel
21 First lens group
22 Second lens group
24 guide tube
25 Cam cylinder
41 First lens frame
42 First frame body
42a6 6th lens holding part which constitutes the 1st lens holding part
42a7 Seventh lens holding part constituting the first lens holding part
43 First support piece
46 1st cam follower
51 Second lens frame
52 Second frame body
52a8 Eighth lens holding part constituting the second lens holding part
52a9 9th lens holding part which constitutes 2nd lens holding part
52a10 10th lens holding part which constitutes 2nd lens holding part
52a11 Eleventh lens holding portion constituting the second lens holding portion
53 Second support piece
56 Second Cam Follower
64 Guide groove
71 First cam groove
72 2nd cam groove L6 6th lens which comprises 1st lens L7 7th lens which comprises 1st lens L8 8th lens which comprises 2nd lens L9 9th lens which comprises 2nd lens L10 Tenth lens constituting the second lens L11 Eleventh lens constituting the second lens O Optical axis

Claims (4)

A first lens is provided which includes a first lens frame provided with a first lens, a first lens holding portion for holding the first lens, and a first cam follower, and is supported to be movable back and forth along the optical axis. Lens group,
A second lens, a second lens holding portion that holds the second lens, and a second lens frame provided with a second cam follower, and is supported movably back and forth along the optical axis. Two lens groups;
A first cam groove that engages with the first cam follower and a second cam groove that engages with the second cam follower are provided, and the first cam groove and the second cam groove are at least partly of each other. A lens barrel comprising: a cam barrel positioned on the same plane orthogonal to the optical axis and supported rotatably about the optical axis. The first lens frame has a cylindrical first frame main body provided with a first lens holding portion on the inner peripheral side, and a plurality of first lens frames project from the first frame main body along the optical axis direction. A first support piece portion, and a first cam follower projecting from the first support piece portion to the outer peripheral side.
The second lens frame has a cylindrical second frame main body provided with a second lens holding portion on the inner peripheral side, and a plurality of second lens frames project from the second frame main body along the optical axis direction. A second support piece, and a second cam follower projecting from the second support piece to the outer peripheral side,
The lens barrel according to claim 1, wherein the first support piece portion and the second support piece portion are alternately arranged in a circumferential direction along an inner side of the cam tube. Provided with a cylindrical guide tube provided with a guide groove along the optical axis direction,
The first lens frame and the second lens frame engage the first cam follower and the second cam follower with the guide groove, and the first frame main body and the second frame main body are inside the guide tube. It is arranged on the circumferential side so as to be movable back and forth along the optical axis direction,
The cam cylinder engages the first cam follower penetrating the guide groove with the first cam groove, engages the second cam follower penetrating the guide groove with the second cam groove, and guides the cam barrel. The lens barrel according to claim 2, wherein the lens barrel is fitted to the outer peripheral side of the tube and arranged to be rotatable. A light source;
A light modulating means for modulating light emitted from the light source;
A projector apparatus comprising: the lens barrel according to claim 1, which projects light modulated by the light modulation means.

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