JP4387918B2 - Lens barrel - Google Patents

Description

  The present invention relates to a lens barrel provided in a camera or the like and having a photographing lens, and a camera including the lens barrel.

  Conventionally, a film camera using a silver salt film and a digital camera capable of photographing with an imaging device are known and widely used. In recent years, for the purpose of improving the portability of the camera, etc., technology development of an internal mechanism for reducing the size of the camera and increasing the focal length change rate (zoom magnification) has been carried out, and various technologies have been proposed. Yes.

  As a camera, there is a zoom camera that can change the focal length of a photographing lens that is generally provided, and a single-focus camera that is fixed at a fixed focal length. These cameras are generally equipped with a lens barrel capable of extending and retracting the photographing lens in order to reduce the size of the camera when not photographing and to change the focal length when photographing. It is.

  Since the camera is a device that the user carries and uses, normal operation is maintained even when the user unexpectedly drops or applies a load, that is, when an external force is applied to the camera. I have to ask. The above-described lens barrel generally protrudes from the camera body when the camera is turned on, and is thus susceptible to external forces. In particular, the tendency is remarkable in the lens barrel in which the magnification of the photographing lens has been increased in recent years.

  If the lens barrel is deformed by an external force, it not only affects the captured image, but in the worst case, the camera may become unusable. Therefore, the lens barrel needs to have a structure that is strong against external force.

  However, making the lens barrel strong against external forces increases the size of the lens barrel (camera). Therefore, various structures have been proposed for preventing the influence of external force without enlarging the lens barrel.

The applicant of the present application has also proposed a structure (see Patent Document 1) that prevents destruction of the lens barrel against inadvertent external force. Further, a technique has been proposed in which the camera function is not impaired by changing camera control when an external force is applied to the lens barrel (see Patent Document 2).
JP 2001-337260 A (paragraph 0041, FIG. 10) JP 7-49446 A (first page)

  In Patent Document 1, a first protrusion is provided on a movable cam ring, and a second protrusion that can contact the first protrusion is provided on a fixed cylinder. However, since the lens barrel driving cam groove and the two protrusions are arranged in parallel with respect to the optical axis direction, a thickness is required in the optical axis direction. As a result, the lens barrel has a strong structure against external forces, but there is a problem that the thickness of the camera becomes thick (the camera becomes large).

  Moreover, in the said patent document 2, after detecting the external force of a lens-barrel, the technique which changes control of a camera is disclosed. Even if an external force is applied to the camera, the camera normally recovers itself, so that the captured image is not affected. However, since the external force is detected based on the information that the lens barrel is moving, it is not effective when the camera stops the focal length changing operation (zooming operation).

  A characteristic configuration of the lens barrel according to the present invention includes a first cylindrical member having a lens member disposed on the inner side thereof, and a second cylindrical member disposed on the outer side of the first cylindrical member. A lens barrel capable of moving the lens member in the direction of the optical axis by rotating the first cylindrical member and the second cylindrical member relatively around the optical axis, A cam groove portion and a first engagement portion are provided in one of the cylindrical members of the first cylindrical member and the second cylindrical member, and the second cylindrical member is engaged with the cam groove portion. And a third engaging portion that can come into contact with the first engaging portion, and the imaging region of the cam groove and the first engaging portion are circles of the one cylindrical member. That is, they are provided in different phases with respect to the circumferential direction.

  Further, another characteristic configuration of the lens barrel according to the present invention includes a first cylindrical member in which a lens member is disposed on the inner side and a second cylindrical member disposed on the outer side of the first cylindrical member. A lens barrel capable of moving the lens member in the optical axis direction by relatively rotating the first cylindrical member and the second cylindrical member around the optical axis. A cam groove portion and a first engagement portion are provided in one of the first cylindrical member and the second cylindrical member, and the other cylindrical member is engaged with the cam groove portion. A second engaging portion and a third engaging portion capable of contacting the first engaging portion are provided, and the imaging region portion of the cam groove portion and the first engaging portion are arranged on the optical axis. It is in a region on a vertical plane.

  Further, another characteristic configuration of the lens barrel according to the present invention includes a first cylindrical member in which a lens member is disposed on the inner side and a second cylindrical member disposed on the outer side of the first cylindrical member. A lens barrel capable of moving the lens member in the optical axis direction by relatively rotating the first cylindrical member and the second cylindrical member around the optical axis. A cam groove portion and a first engagement portion are provided in one of the first cylindrical member and the second cylindrical member, and the other cylindrical member is engaged with the cam groove portion. A second engaging portion and a third engaging portion capable of contacting the first engaging portion are provided, and a length of the third engaging portion in a circumferential direction is the first engaging portion; It is longer than the engaging portion.

  According to the present invention, either one of the first tubular member and the second tubular member is provided with the cam groove portion and the first engaging portion, and the other tubular member has the cam groove portion. A cam pin portion that engages with the first engagement portion, and a second engagement portion that can abut against the first engagement portion. The imaging region of the cam groove portion and the first engagement portion are the one cylindrical member. By providing the lens barrels in different phases with respect to the circumferential direction, a lens barrel that is strong against external force is provided without impairing driving of the lens barrel or requiring special camera control. be able to.

  Further, it is possible to provide a lens barrel that can be applied at a higher magnification by the configuration in which the imaging region portion of the cam groove portion and the first engagement portion are in a region on substantially the same plane perpendicular to the optical axis. it can. In addition, when a photographic lens having a fixed extension amount is provided, a lens barrel that can reduce the retractable length of the camera compared to the known technology and that can reduce the size of the camera is provided. Can do.

  The circumferential length of the first engaging portion and the second engaging portion is such that the second projecting portion is longer than the first projecting portion when the camera is turned on. It is possible to provide a configuration applicable in any case.

  Hereinafter, details of the present invention will be described with reference to examples and drawings.

  FIG. 1 shows a camera according to an embodiment of the present invention, and reference numeral 1 denotes a camera body. A lens barrel 2 capable of changing the focal length of the photographing lens is provided on the front surface of the camera body 1. In addition, a light emission window 3 constituting a strobe device that irradiates a subject with illumination light is provided on the front surface of the camera body 1, and a finder window 4 is provided on the left side of the light emission window 3.

  Further, a release button 5 is provided on the upper surface of the camera body 1 to start a shooting preparation operation (focus adjustment operation and photometry operation) and a shooting operation (exposure to an image sensor such as a film or a CCD). FIG. 1 is a typical schematic diagram of a camera, and the present embodiment is not limited to the above configuration.

  FIG. 2 shows a central sectional view of the lens barrel 2 with the lens barrel 2 extended. 6 is a first group lens unit including a first group photographing lens, 7 is a second group lens unit including a shutter unit and a second group photographing lens, 8 is a third group unit including a third group photographing lens, and 9 is an image sensor. It is a base member.

  Reference numeral 10 denotes a rectilinear cylinder for linearly restricting the first group lens unit 6 when the lens barrel is driven, and 11 is a movable cam ring (first lens) provided with cams for driving the first group lens unit and the second group lens unit. Reference numeral 12 denotes a fixed cylinder (corresponding to a second cylindrical member) provided with a cam for driving the movable cam ring 11. Since the configuration and driving method of the lens barrel are conventionally known techniques, a detailed description is omitted, but the configuration is not limited to the above configuration as long as the configuration satisfies the characteristics of the present invention.

  The characteristic technique of the present embodiment will be described below.

  FIG. 3 shows the moving cam ring 11. Reference numeral 11a denotes a static pressure rib (corresponding to a third engaging portion) that engages with a fixed cylinder 12 to be described later when an external force is applied, and is provided on the outer side in the optical axis direction of the outer peripheral surface of the movable cam ring 11. The rib shape is formed in a certain length along the circumferential direction, and the rib shape having the same configuration is provided at three locations along the circumferential direction. Reference numeral 11b denotes a cam pin that engages with the cam groove 11d to drive the movable cam ring 11 along the cam groove provided in the fixed cylinder 12, and the static pressure rib 11a and the circumference are arranged on the outer peripheral surface of the movable cam ring 11. It is provided at three locations corresponding to the respective static pressure ribs 11a on substantially the same direction line. 11c is a drive gear for rotating the movable cam ring 11 via a reduction gear train connected from a lens barrel drive motor (not shown), and is provided on the outer peripheral surface of the movable cam ring 11 at the end in the optical axis direction. It has been. A cam groove 11 d for driving the lens unit is provided on the inner peripheral surface of the movable cam ring 11.

  FIG. 4 shows the fixed cylinder 12. Reference numeral 12a denotes a static pressure rib (corresponding to a first engaging portion) that engages with the static pressure rib 11a of the moving cam ring 11, and is provided on the front side in the optical axis direction of the inner peripheral surface of the fixed cylinder 12. It is formed in a rib shape having a fixed length along the same direction line, and the rib shape having the same configuration is provided at three locations along the same line in the circumferential direction. A cam groove 12b is engaged with the cam pin 11b of the movable cam ring 11 to drive the lens barrel. The cam groove 12b is provided at three locations corresponding to the cam pin 11b of the movable cam ring 11 on the inner peripheral surface of the fixed cylinder 12, and guides the cam pin 11b while being skewed in the optical axis direction. And a portion (imaging region portion) for guiding in the circumferential direction on the front side. The imaging region portion of the cam groove 12b is provided alternately with the static pressure rib 12a with a phase shifted in the circumferential direction. The photographing region portion of the cam groove 12b is provided in a region on substantially the same plane perpendicular to the static pressure rib 12a and the optical axis direction.

  When the cam pin 11b of the moving cam ring 11 is guided to the photographing region portion of the cam groove 12b, the cam pin 11b and the cam groove 12b are provided on the substantially same line in the circumferential direction as the static pressure ribs 11a and 12a, respectively. As shown in FIG. 2B, the static pressure rib 11a of the movable cam ring 11 and the static pressure rib 12a of the fixed cylinder 12 are arranged so as to be close to each other in the optical axis direction and come into contact with each other.

  When the camera is turned on and the lens barrel 2 is extended forward in the optical axis direction from the camera body, the movable cam ring 11 rotates in the circumferential direction along the drive cam 12b provided inside the fixed barrel 12. After advancing in the optical axis direction, it stops at a predetermined focal length position (for example, FIG. 2) in the imaging region portion of the cam 12b. At this time, the relationship between the static pressure rib 11a provided to the movable cam ring 11 and the static pressure rib 12a provided to the fixed cylinder 12 is arranged close to the optical axis direction as shown in FIG. 2B. Become so.

  In the state of FIG. 2, when some external force F (for example, the user accidentally hits the camera) is applied to the direction of the figure (the back side with respect to the optical axis direction) in FIG. With this configuration, the movable cam ring 11 and the static pressure ribs 11a, 12a of the fixed cylinder 12 come into contact with each other and hold their positions. That is, the lens barrel has a strong structure against external force applied to the barrel.

  FIG. 5 shows a comparison view of the development of the fixed cylinder 12 of the present embodiment and the development of the known fixed cylinder. In FIG. 5, (a) is a fixed cylinder of this embodiment, and (b) is a known fixed cylinder.

  In order to increase the magnification of the camera, it is necessary to increase the length in the optical axis direction of the drive cams 12b and 11d provided in the fixed cylinder 12 and the movable cam ring 11 so that the lens barrel can drive the lens larger. is there. In FIG. 5 (a), when the drive amount L of the drive cam 12b provided in the fixed cylinder 12 is increased, the moving-out amount of the movable cam ring 11 is increased, and a lens barrel corresponding to high magnification is obtained. On the other hand, as described above (as shown in the abutting state in FIG. 2B), the static pressure rib 12 a provided in the fixed cylinder 12 is not close to the static pressure rib 11 a provided in the moving cam ring 11. It cannot withstand external forces. Therefore, in order to increase the feeding amount L of the movable cam ring 11 and satisfy the functions of the static pressure ribs 11a and 12a, it is necessary to dispose the static pressure rib 12a as far forward as possible in the optical axis direction.

  In the known technique shown in FIG. 5B, the cam groove 12b and the static pressure rib 112a are arranged in parallel so as to overlap in the optical axis direction.

  On the other hand, in this embodiment shown in FIG. 5A, the static pressure rib 12a and the drive cam 12b in the imaging region are arranged with a phase shifted with respect to the angular direction of the optical axis as shown in the figure. That is, the drive cams 12b and the static pressure ribs 12a in the imaging region are alternately arranged in the circumferential direction of the fixed cylinder 12. By adopting such a configuration, the static pressure rib 12a and the drive cam 12b do not overlap in the optical axis direction, so that the drive cam 12b can be disposed more forward in the optical axis direction, and the lens barrel fixed cylinder 12 is provided. The length of the drive cam 12b in the optical axis direction can be increased by (C2-C1) compared to FIG. 5B.

  Further, in the present embodiment, the static pressure rib 12a is formed in the same plane as the cam groove 12b for driving the movable cam ring 11 in the optical axis direction (O: arrow direction subject side) of the fixed cylinder 12. Configure the area.

  By adopting such a configuration, it is possible to dispose the aforementioned static pressure rib 12a as far as possible in the optical axis direction, and as a result, the driving amount L of the lens barrel can be increased as compared with the known technique. Is possible. Therefore, it is possible to provide a lens barrel with a high magnification. In comparison with the premise of using the same photographic lens as that of the known art, in this embodiment, it is possible to increase the extension amount of the lens barrel with the same retractable length, and therefore the retractable length of the lens barrel is shortened. It becomes possible. As a result, the camera can be downsized.

  Further, according to the configuration in which the static pressure rib 12a and the cam groove 12b of the fixed cylinder 12 are provided on a plane perpendicular to the optical axis direction, the static pressure rib 11a and the cam pin 11b on the movable cam ring 11 side are further associated with each other. Therefore, the movable cam ring 11 can be provided on a substantially flat surface perpendicular to the optical axis direction, and the movable cam ring 11 and the fixed cylinder 12 are less overlapped when the movable cam ring 11 is extended forward in the optical axis direction. 11 can be arranged as far forward as possible in the optical axis direction.

  The operation of the static pressure rib 11a of the moving cam ring 11 of the lens barrel and the static pressure rib 12a of the fixed cylinder 12 in the configuration of the above-described embodiment will be described with reference to FIG.

  FIG. 6 shows a development view of the fixed cylinder 12 of this embodiment, as in FIG. 5. For the sake of easy explanation, the relationship between the static pressure rib 11a of the movable cam ring 11, the cam 12b of the fixed cylinder 12, and the static pressure rib 12a. Only shown and exaggerated in the optical axis direction.

  FIG. 6A shows a camera power OFF state (standby retracting state of the lens barrel). Since the movable cam ring 11 is in the retracted state of the lens barrel when the camera is turned off, the static pressure rib 11a of the movable cam ring 11 is on the back side in the optical axis direction and is not in contact with the static pressure rib 12a of the fixed cylinder 12.

  When the power of the camera is turned on and the lens barrel is extended from the state of FIG. 6A, the static pressure rib 11a of the movable cam ring 11 is shown in D in the same figure as the cam locus of the cam groove 12a of the fixed cylinder 12. It operates on the trajectory. FIG. 6B shows the wide state of the camera.

  At this time, the static pressure rib 11a of the movable cam ring 11 and the static pressure rib 12a of the fixed cylinder 12 can be engaged and contacted in the region E in the drawing. At this time, even if an external force is applied to the lens barrel as described above, the external force can be supported in the E region, so that the lens barrel is not destroyed.

  Further, FIG. 6C is a diagram when the focal length is most rotated to the telephoto side. The static pressure rib 11a of the movable cam ring 11 and the static pressure rib 12a of the fixed cylinder 12 can be engaged and contacted in the region F in the same manner as in FIG. That is, as with the wide side, even if an external force is applied to the lens barrel, the external force is supported in the F region, so that the lens barrel is not destroyed.

The relationship between the length L1 of the static pressure rib 11a of the moving cam ring 11 and the length L2 of the static pressure rib 12a of the fixed cylinder 12 shown in FIG.

Length of static pressure rib 11a of moving cam ring 11: L1> Length of static pressure rib 12a of fixed cylinder 12: L2

It is composed. With this configuration, zooming is possible while maintaining the state between (b) to (c) of FIG. 6 even when the camera has a focal length between wide and tele. That is, in this embodiment, it is possible to provide a structure that is strong against external force at any focal length at the time of shooting by the camera.

  As described above, in the present embodiment, the static pressure rib and the cam of the imaging region are arranged with a phase shifted with respect to the rotational direction of the optical axis view, and then the imaging region portion of the cam groove provided in the fixed cylinder Since the static pressure ribs are arranged on substantially the same plane perpendicular to the optical axis, the lens barrel can be extended more greatly. For this reason, a lens barrel capable of high magnification can be configured. Furthermore, since the static pressure rib of the moving cam ring is configured to be longer than the static pressure rib of the fixed cylinder, it is possible to provide a structure that is strong against external force regardless of the state of power-on of the camera. . That is, according to the present embodiment, it is possible to provide a lens barrel that can cope with a high magnification or can be downsized and is strong against external force.

  The present invention is not limited to the above-described embodiment. For example, the cam groove and the static pressure rib are arranged in the moving cam ring with the phases shifted in the circumferential direction, and the cam pin and the static pressure rib are provided in the fixed cylinder. be able to.

It is a general | schematic perspective view of the camera outline | summary which concerns on the Example of this invention. It is a center sectional view of a lens barrel concerning an example of the present invention. It is an external appearance perspective view of the moving cam ring which concerns on the Example of this invention. It is an external appearance perspective view of the fixed cylinder which concerns on the Example of this invention. FIG. 2A is a development view of a fixed cylinder according to an embodiment of the present invention, and FIG. It is an expanded view of the fixed cylinder which concerns on the Example of this invention, and is a wide state (b) and a tele state (c) at the time of power-off (a).

Explanation of symbols

1: camera body 2: lens barrel 3: strobe window 4: finder window 5: release button 6: 1 group unit 7: 2 group unit 8: 3 group unit 9: base member 10: rectilinear cylinder 11: moving cam ring, 11a: Static pressure rib (first protrusion of the present application), 11b: Drive cam pin, 11c: Drive gear, 11d: Cam groove 12: Fixed cylinder, 12a: Static pressure rib (second protrusion of the present application), 12b : Drive cam groove

Claims (8)

  A first cylindrical member having a lens member disposed inside; and a second cylindrical member disposed outside the first cylindrical member, wherein the first cylindrical member and the second cylindrical member are provided. A lens barrel capable of moving the lens member in the optical axis direction by relatively rotating around the optical axis of the first cylindrical member and the second cylindrical member. One of the cylindrical members is provided with a cam groove portion and a first engagement portion, and the other cylindrical member is in contact with the second engagement portion and the first engagement portion. A contactable third engaging portion is provided, and the imaging region of the cam groove and the first engaging portion are provided in different phases with respect to a circumferential direction of the one cylindrical member. A lens barrel.   2. The lens barrel according to claim 1, wherein the imaging region portion of the cam groove portion and the first engaging portion are in a region on substantially the same plane perpendicular to the optical axis.   3. The lens barrel according to claim 1, wherein a length of the third engagement portion in a circumferential direction is longer than that of the first engagement portion.   A first cylindrical member having a lens member disposed inside; and a second cylindrical member disposed outside the first cylindrical member, wherein the first cylindrical member and the second cylindrical member are provided. A lens barrel capable of moving the lens member in the optical axis direction by relatively rotating around the optical axis of the first cylindrical member and the second cylindrical member. One of the cylindrical members is provided with a cam groove portion and a first engagement portion, and the other cylindrical member is in contact with the second engagement portion and the first engagement portion. A lens barrel characterized in that a third engaging portion that can be contacted is provided, and the photographing region portion of the cam groove portion and the first engaging portion are in a region on a plane perpendicular to the optical axis.   A first cylindrical member having a lens member disposed inside; and a second cylindrical member disposed outside the first cylindrical member, wherein the first cylindrical member and the second cylindrical member are provided. A lens barrel capable of moving the lens member in the optical axis direction by relatively rotating around the optical axis of the first cylindrical member and the second cylindrical member. One of the cylindrical members is provided with a cam groove portion and a first engagement portion, and the other cylindrical member is in contact with the second engagement portion and the first engagement portion. A lens barrel characterized in that a third engaging portion capable of contacting is provided, and a circumferential length of the third engaging portion is longer than that of the first engaging portion.   The lens barrel according to claim 1, wherein the second engagement portion is a cam pin.   The lens barrel according to claim 1, wherein the first and third engaging portions are projecting members.   A camera comprising the lens barrel according to claim 1.

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