Abstract:
A zoom lens unit includes a zoom ring that has a scale indicating a focal length of the zoom lens unit, an indicator member that points a desired value on the scale, and a selection mechanism that is configured to select one of first and second moving states of the indicator member. In the first moving state, the indicator member moves as the zoom ring rotates. Further, in the second moving state, the indicator member moves without rotating the zoom ring.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application is a continuation of PCT Application No. PCT/JP2015/061412 filed Apr. 14, 2015 which claims priority to Japanese Patent Application No. 2014-105378 filed May 21, 2014 which are hereby expressly incorporated by reference herein in their entireties. 
     
    
     BACKGROUND 
       [0002]    The present invention relates to a zoom lens unit and an indicator member. 
         [0003]    A zoom lens unit that is provided with a zoom ring having a scale showing a focal length is known. The focal length is changed according to a rotation amount of the zoom lens unit when a user performs a rotation (zoom) operation on the zoom lens unit. See, for example, Japanese Patent Publication No. 2007-298672. 
         [0004]    In the zoom lens unit explained above, it is common that the focal length is continuously (steplessly) changed by the rotation of the zoom ring. Therefore, it is difficult that after the focal length between lines of the scale is adjusted once, the same focal length is reproduced later. 
       SUMMARY 
       [0005]    The present invention attempts to solve the problems explained above. An object of the present invention is to provide a zoom lens unit and an indicator member that make it easy reproduce a focal length that was once adjusted. 
         [0006]    To achieve the above object, a zoom lens unit according to one aspect of the present invention includes: a zoom ring that has a scale indicating a focal length of the zoom lens unit; an indicator member that points a desired value on the scale; and a selection mechanism that is configured to select one of first and second moving states of the indicator member. In the first moving state, the indicator member moves as the zoom ring rotates. Further, in the second moving state, the indicator member moves without rotating the zoom ring. 
         [0007]    In the zoom lens unit according to the above aspect of the present invention, the zoom ring is configured with first and second half ring members. The first and second half ring members are attachable to each other to configure the zoom ring in a ring shape. 
         [0008]    In the zoom lens unit according to the above aspect of the present invention, the selection mechanism includes an energization member. The energization member is located between the zoom ring and the indicator member so as to energize the zoom ring and the indicator member. When the zoom ring and the indicator member are energized by the energization member, a relative location of the zoom ring and the indicator member is fixed so that the indicator member moves as the zoom ring rotates in the first moving state. 
         [0009]    An indicator member according to another aspect of the present invention, which points a desired value on a scale indicating a focal length attached to a zoom ring, the indicator member includes: a selection mechanism that is configured to select one of first and second moving states of the indicator member. In the first moving state, the indicator member moves as the zoom ring rotates. Further, in the second moving state, the indicator member moves without rotating the zoom ring. 
         [0010]    In the indicator member according to the above aspect of the present invention, the zoom ring is configured with first and second half ring members. The first and second half ring members are attachable to each other to configure the zoom ring in a ring shape. 
         [0011]    In the indicator member according to the above aspect of the present invention, the selection mechanism includes an energization member which energizes the zoom ring. When the zoom ring is energized by the energization member, a relative location of the zoom ring and the indicator member is fixed so that the indicator member moves as the zoom ring rotates in the first moving state. 
         [0012]    The present invention can provide a zoom lens unit that can make it easy to reproduce a focal length that was once adjusted, and an indicator member. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIG. 1  is a front view that shows a zoom lens unit according to an embodiment of the present invention. 
           [0014]      FIG. 2  is an exploded perspective view that shows an indicator member, which is disassembled, of the zoom lens unit according to the embodiment of the present invention when viewed from rear and right side surface sides of the zoom lens unit shown in  FIG. 1 . 
           [0015]      FIG. 3  is an A-A cross-sectional schematic view of the zoom lens unit shown in  FIG. 1  and shows only a zoom ring, the indicator member and a coil spring according to the embodiment of the present invention. 
           [0016]      FIG. 4  is a B-B cross-sectional schematic view of the zoom lens unit shown in  FIG. 1  and shows only a set of the zoom ring and the indicator member according to the embodiment of the present invention. 
           [0017]      FIGS. 5A and 5B  are schematic views of a region C of the zoom lens unit shown in  FIG. 1  according to the embodiment of the present invention. 
           [0018]      FIG. 6  is a diagram that shows a variation of the zoom lens unit according to the embodiment of the present invention.  FIG. 6  shows a part that corresponds to a configuration shown in  FIG. 4  of the zoom lens unit according to the embodiment of the present invention. 
       
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       [0019]    A configuration and an operation of a zoom lens unit and an indicator member according to an embodiment of the present invention. 
         [0020]    As discussed below, a zoom lens unit and an indicator member according to an embodiment of the present invention will be explained with reference to the drawings.  FIG. 1  a front view that shows the zoom lens unit according to the embodiment of the present invention.  FIG. 2  is an exploded perspective view that shows the indicator member, which is disassembled, of the zoom lens unit according to the embodiment of the present invention when viewed from rear and right side surface sides of the zoom lens unit shown in  FIG. 1 . 
         [0021]    A zoom lens unit  1  has an annular zoom ring  2  having a scale S that shows a focal length. Specifically, the focal length is changed is changed according to a rotation amount of the zoom lens unit  1  when a user performs a rotation (zoom) operation on the zoom lens unit  1  (a direction indicated by the arrow R in  FIG. 2  and the rotation of a circumferential direction of the zoom lens unit  1 ). Further, the zoom lens unit  1  has an annular indicator member  3  that indicates a desired value (any value) on the scale S. 
         [0022]    As shown in  FIG. 2 , ends  3 A 1  and  3 A 2  of a disassembled indicator member  3 A that is one part of the indicator member  3  are respectively fixed to ends  3 B 1  and  3 B 2  of a disassembled indicator member  3 B that is the other part of the indicator member  3  by screws  3 D. Specifically, the end  3 A 1  of the disassembled indicator member  3 A is fixed to the end  3 B 1  of the disassembled indicator member  3 B. Further, the end  3 A 2  of the disassembled indicator member  3 A is fixed to the end  3 B 2  of the disassembled indicator member  3 B. As a result, it becomes the annular indicator member  3  shown in  FIGS. 1 and 3 . Further, an orientation of letters (numbers) on the scale S shown in  FIG. 2  is opposite to that on the scale S shown in  FIG. 1 . This is because  FIG. 2  is the diagram of the zoom lens unit when viewed from the rear side,  FIG. 2  shows the diagram in which the scale S of the zoom lens unit  1  shown in  FIG. 1  (the front view) is not seen in a view angle in  FIG. 2 . In the same manner, the scale S shown in  FIG. 2  is not seen in  FIG. 1 . Because the scale S respectively shown in  FIGS. 1 and 2  is provided on the same zoom ring  2 , the same reference characters “S” are used for Labeling. 
         [0023]      FIG. 3  is an A-A cross-sectional schematic view of the zoom lens unit  1  shown in  FIG. 1  and shows only the zoom ring  2 , the indicator member  3  and a coil spring  4  explained below.  FIG. 4  is a B-B cross-sectional schematic view of the zoom lens unit  1  shown in  FIG. 1  and shows only a set of the zoom ring  2  and the indicator member  3 . 
         [0024]    The indicator member  3  is formed in the zoom ring  2  and is fitted into a groove  2 A that is provided in a circumferential direction of the zoom lens unit  1  shown in  FIG. 1 . In this case, it could be said that it is not appropriate to express the groove  2 A as “groove” based on only the sectional shape of the zoom ring  2  shown in  FIG. 4 . However, a section height dimension of a member Y that is located adjacent to the zoom ring  2  shown in  FIG. 4  is the same as a section height dimension (a greatest value) of the zoom ring  2 . Therefore, a smaller part (the groove  2 A) of the sectional height dimensions compared to the sectional height dimension (the greatest value) of the zoom ring  2  is expressed as “groove” by looking along with a wall Y 1  of the member Y. 
         [0025]    The coil springs  4  that correspond to an energization member are interposed at two locations between the indicator member  3  and the zoom ring  2  at upper and lower portions as shown in  FIG. 3 . One end  4 A of the coil spring  4  is attached so as to be fixed to a side of the indicator member  3 . The other end  4 B that is located at an opposite side of the one end  4 A of the coil spring  4  has a spherical member (not shown) that contacts the groove  2 A and at the same time, is slidable with respect to the groove  2 A. Each of the coil springs  4  is fixed to a center in a length direction of each of the disassembled indicator members  3 A and  3 B shown in  FIG. 2 . 
         [0026]    Further, the coil spring  4  is compressed between the indicator member  3  and the groove  2 A so that the coil spring  4  energizes both the indicator member  3  and the zoom ring  2 . Due to this energizing force of the coil spring  4 , a relative position of the indicator member  3  and the zoom ring  2  is fixed. Further, the reason why there is a gap X between the groove  2 A and the indicator member  3  in  FIGS. 3 and 4  is because the gap X is required for having the coil spring  4  and the spherical member (not shown) between the groove  2 A and the indicator member  3 . 
         [0027]    In a state in which the relative position of the indicator member  3  and the zoom ring  2  is fixed, when the zoom rig  2  rotates along the arrow R, the indicator member  3  also rotates with the rotation of the zoom ring  2 . Further, it is also possible that while the zoom ring  2  is fixed so as not to rotate along the arrow R, the indicator member  3  can also rotate along the arrow R independently with respect to the zoom ring  2 . When the indicator member  3  rotates along the arrow R independently with respect to the zoom ring  2 , the spherical member explained above slides with respect to the zoom ring  2 . 
         [0028]    In other words, a user who uses the zoom lens unit  1  can select one of moving states of the indicator member  3  explained above, i.e., (1) the rotation with the rotation of the zoom ring  2  and (2) the rotation without the rotation of the room ring  2 . Further, the energizing force of the coil spring  4  makes it possible to perform the rotation of the moving state (1). 
         [0029]      FIGS. 5A and 5B  are schematic views of a region C of the zoom lens unit  1  shown in  FIG. 1 . When the user performs a rotation (zoom) operation on the zoom ring  2  along the arrow R by the user, the focal length is changed according to the rotation amount.  FIG. 5A  shows a state in which the focal length that the user is satisfied with is determined. In the above state, an index line  5  (a fixed line of which a position is not changed even by rotating the zoom ring  2 ) indicates a point located between the value “10” and the value “11” of the scale S. While the user fixes the zoom ring  2  in the above state so as not to be rotated, only the indicator member  3  is rotated along the direction of the arrow R so as to make a position of an indicator  3 C of the indicator member  3  be aligned to the position of the index line ( FIG. 5B ). Thereafter, the relative position of the indicator member  3  and the zoom ring  2  remains as a fixed state by the energizing force of the coil spring  4 . As a result, although the user rotates the zoom ring  2  so as to adjust another focal length that is different from the focal length being previously set (satisfied), it is possible to easily reproduce the previous focal length with which the user is satisfied by aligning the position of the indicator  3 C to the position of the index line  5  again as shown in  FIG. 5B . 
       Main Effects that are Obtained by the Embodiment of the Present Invention 
       [0030]    As explained above, the zoom lens unit  1  according to the embodiment of the present invention can easily reproduce the focal length that is adjusted in the past. Similarly, at the time of using the zoom lens unit  1 , the indicator member  3  according to the embodiment of the present invention can also easily reproduce the focal length that is adjusted in the past. 
         [0031]    Further, the spherical member (not shown), which contacts the groove  2 A and at the same time, is slidable with respect to the groove  2 A, is attached to the other end  4 B of the coil spring  4 . Because the spherical member is used, the sliding between the other end  4 B and the groove  2 A is performed very smoothly, and operability for the user can be great. 
         [0032]    Further, the indicator member  3  is fitted into the groove  2 A that the zoom ring  2  has and that is formed in the circumferential direction of the zoom lens unit  1 . Therefore, when the other end  4 B of the coil spring  4  and the groove  2 A are slid while contacting, because the groove  2 A becomes a guide of the indicator member  3 , a positional misalignment hardly occurs. 
       Other Embodiment 
       [0033]    The zoom lens unit  1  and the indicator member  3  according to the embodiments of the present invention explained above are an example of the ideal embodiment of the present invention. Therefore, it will be apparent that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be apparent to one of ordinary skill in the art are intended to be included within the scope of the following claims. 
         [0034]    For instance, the spherical member (not shown), which contacts the groove  2 A and at the same time, is slidable with respect to the groove  2 A, is attached to the other end  4 B of the coil spring  4 . However, because the spherical member is not an essential member, it can be omitted. Further, it is also possible that a plate member instead of the spherical member is fixed to the other end  4 B of the coil spring  4  so as to contact the groove  2 A and at the same time, to be slidable with respect to the groove  2 A by such as a plate surface of the plate member. 
         [0035]    Further, because the coil spring  4  that corresponds to the energization member is also not an essential member, it can also be omitted. Further, the energization member, such as the coil spring  4 , is attached so as to make the one end  4 A of the coil spring  4  be fixed to the zoom ring  2 . In addition, the other end  4 B of the coil spring  4  can also contact and at the same time, be slidable with respect to the indicator member  3 . Also, the energization member is not limited to the coil spring  4 , and can also be such as a plate spring. 
         [0036]    The zoom lens unit  1  has the index line  5 . However, because the index line  5  is not an essential component, it is also possible not to be provided. It is also possible to reproduce the focal length that is adjusted in the past by aligning the position of the indicator  3 C of the indicator member  3  to a portion of the other members of the zoom lens unit  1  instead of the index line  5 . 
         [0037]    Further, the indicator member  3  has a configuration of being disassembled into the disassembled indicator members  3 A and  3 B. However, instead of adopting this configuration explained above, it is also possible to make the indicator member  3  by configuring and assembling with three or more pieces of disassembled indicator members, or by configuring with a single ring-shaped member. Each of the coil springs  4  is fixed to the center in the length direction of each of the disassembled indicator members  3 A and  3 B. However, the number of fixing locations of the coil springs  4  or an arrangement position can be set appropriately. 
         [0038]    Further, as shown in  FIGS. 3 and 4 , the coil spring  4  energizes the zoom ring  2  and the indicator member  3  in a radial direction of the zoom lens unit  1  shown in  FIG. 1 . However, the energization member, such as the coil spring  4 , can also energize the zoom ring  2  and the indicator member in different directions other than the above radial direction. 
         [0039]    For instance,  FIG. 6  is a diagram that shows a variation of the zoom lens unit  1  according to the embodiment of the present invention and that shows a part that corresponds to the zoom lens unit  1  shown in  FIG. 4 . Here, a zoom lens unit  11  according to the variation of the zoom lens unit  1  according to the embodiment of the present invention energizes the zoom ring  2  and the indicator member  3  in a length direction (a vertical direction in  FIG. 1 ). 
         [0040]    In  FIG. 6 , in regards to the zoom lens unit  11 , the same reference numerals in the zoom lens unit  1  are used for labeling for the same constituting members as the zoom lens unit  1 . Thus, the redundant explanations with respect to the common constituting members between the zoom lens unit  1  and the zoom lens unit  11  are omitted. 
         [0041]    In  FIG. 6 , the coil spring  4  is interposed between the zoom ring  2  and the indicator member  3  in the length direction of (the vertical direction or an up down direction in  FIG. 1 ) of the zoom lens unit  11  so as to energize them. Therefore, there is no gap X between the groove  2 A and the indicator member  3 . The gap X exists between the zoom ring  2  and the indicator member  3  in the length direction of the zoom lens unit  11 . 
         [0042]    In the same way as the zoom lens unit  1 , the indicator member  3  of the zoom lens unit  11  can also perform both (1) the rotation with the rotation of the zoom ring  2  and (2) the rotation without the rotation of the room ring  2  by the user&#39;s selection. Thus, it is also the same as the zoom lens unit  1  that the energizing force of the coil spring  4  makes it possible to perform the rotation of the above (1). 
         [0043]    Further, the indicator member  3  is fitted into the groove  2 A that the zoom ring  2  has and is formed in the circumferential direction of the zoom lens unit  1 . However, because this groove  2 A is not an essential component of the zoom lens unit  1 , it is also possible not to be provided. Further, though the groove  2 A is configured by combining the zoom ring  2  with the member Y in the embodiment of the present invention, it is also possible to provide the same groove as the groove  2 A by the zoom ring  2  as a single entity. In addition, also in regards to the groove  2 A of the zoom lens unit  11 , it is also possible to provide the same groove as the groove  2 A by the zoom ring  2  as a single entity.