JP2015075705A - Lens barrel and image capturing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mechanism for improving sealability of a lens barrel without increasing a driving load of a movable barrel of the lens barrel, while reducing the size and cost of an image capturing device.SOLUTION: A lens barrel 100a includes; a movable barrel 102 that can move in an optical axis direction; an elastic member 108 which elastically deforms to exert pressing force on an outer periphery 102a of the movable barrel 102, hermetically sealing the outer periphery 102a thereby; and a manipulation part 106 which is movable in the optical axis direction and is rotatable in a circumferential direction and which moves the movable barrel 102 in the optical direction through transmission means 106c, 104b, 104, 104a1, 102c1 when rotationally manipulated. The lens barrel allows for switching between a first state, in which movement of the movable barrel 102 in the optical direction through rotational manipulation of the manipulation part 106 is enabled, and a second state, in which movement of the movable barrel 102 in the optical axis direction through rotational manipulation of the manipulation part 106 is disabled and the elastic member 108 is further deformed to exert more pressing force than in the first state, by moving the manipulation part 106 in the optical axis direction.

Description

  The present invention relates to a lens barrel mounted on an imaging apparatus such as a digital still camera, and an imaging apparatus including the lens barrel.

  In some imaging apparatuses such as a digital still camera, a gap on the outer peripheral side of the movable barrel of the lens barrel is sealed with an elastic member to prevent entry of foreign matters such as water and dust.

  In order to improve the sealing performance of the elastic member to improve the sealing performance to prevent the entry of foreign matter, it is necessary to increase the pressing force on the elastic member and the movable cylinder. However, when the pressing force is increased, the frictional force is increased at the same time, so that the driving load of the movable cylinder increases, resulting in an increase in power consumption and a deterioration in operability.

  Therefore, in order to reduce the driving load of the movable cylinder, a configuration is disclosed that includes action means for applying a force in a direction away from the movable cylinder to the elastic member when the movable cylinder moves (Patent Document 1). ).

JP 7-199316 A

  However, in Patent Document 1, a mechanism for driving the movable barrel of the lens barrel and a mechanism for applying a force to the elastic member in a direction away from the movable barrel are provided separately. There is a problem that the size of the apparatus increases. Further, since it is necessary to separately operate or control the mechanism for driving the movable barrel of the lens barrel and the mechanism for applying a force to the elastic member in the direction away from the movable barrel, the structure of the apparatus is complicated and the cost is increased. There is a problem of becoming high.

  Therefore, the present invention provides a mechanism for improving the sealing performance of the lens barrel while realizing downsizing and cost reduction of the imaging device without increasing the driving load of the movable barrel of the lens barrel. Objective.

  In order to achieve the above object, the lens barrel of the present invention has a movable barrel movable in the optical axis direction and a pressing force for sealing the outer circumferential portion against the outer circumferential portion of the movable barrel by elastic deformation. An elastic member to be actuated, and an operation unit which is movable in a first direction and a second direction different from the first direction, and moves the movable cylinder in the optical axis direction via a transmission means by movement in the second direction. A first state that enables movement of the movable cylinder in the optical axis direction by movement of the operation section in the second direction; and movement of the movable cylinder in the optical axis direction by movement of the operation section in the second direction. And a second state in which the elastic member is further elastically deformed to increase the pressing force from the first state by switching the operating portion in the first direction. Features.

  According to the present invention, it is possible to improve the sealing performance of the lens barrel while reducing the size and cost of the imaging apparatus without increasing the driving load of the movable barrel of the lens barrel.

It is a schematic sectional drawing in alignment with the optical axis direction of the digital still camera as an example of an imaging device provided with the lens barrel which is the 1st embodiment of the present invention. (A) is the figure which looked at the press member from the image surface side to the optical axis direction, (b) is the sectional view on the AA line of (a). It is principal part sectional drawing of the lens barrel for demonstrating the deformation | transformation state of packing when an operation ring is moved to an optical axis direction. It is principal part sectional drawing of the lens barrel for demonstrating the deformation | transformation state of packing when an operation ring is moved to an optical axis direction. (A) is a graph which shows the relationship between the position of the optical axis direction of an operation ring, and the radial inner side pressing force which acts with respect to the outer peripheral part of a movable cylinder from packing. (B) is a graph showing the relationship between the position of the operation ring in the optical axis direction and the pressing force from the packing to the subject side in the optical axis direction acting on the contact surface of the front cover. It is a flowchart figure which shows the example of operation of a digital still camera. (A) is a principal part sectional view showing a state where the movable cylinder is extended toward the subject side in the optical axis direction in the first state, and (b) is a sectional view of the movable cylinder extended toward the subject side in the optical axis direction in the second state. FIG. It is a schematic sectional drawing in alignment with the optical axis direction of the digital still camera as an example of an imaging device provided with the lens barrel which is the 2nd Embodiment of this invention. (A) is a partial development view showing a relationship between the light shielding portion and the sensor in a state where the contact surface of the fixed cylinder and the contact surface of the operation ring are in contact, and (b) is a subject in which the operation ring is in the optical axis direction. It is a partial expanded view which shows the relationship between the light-shielding part and the sensor in the state which moved to the side. It is a schematic sectional drawing in alignment with the optical axis direction of the digital still camera as an example of an imaging device provided with the lens barrel which is the 3rd Embodiment of this invention. (A) is a partial development view showing the relationship between the convex portion and the concave portion in a state where the contact surface of the operation ring is in contact with the contact surface of the fixed cylinder, and (b) is an operation ring from the state of (a). FIG. 4 is a partial development view in a state where the lens is moved to the subject side in the optical axis direction.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a schematic cross-sectional view along the optical axis direction of a digital still camera as an example of an imaging apparatus including a lens barrel that is the first embodiment of the present invention.

  As shown in FIG. 1, in the digital still camera 100 of the present embodiment, a zoom lens barrel 100a is detachably fixed to a camera body 110. The lens barrel 100 a includes a movable cylinder 102, a guide cylinder 103, a cam ring 104, a fixed cylinder 105, an operation ring 106, a front cover 107, a packing 108, and a pressing member 109.

  The movable cylinder 102 is formed in a cylindrical shape, holds the zoom lens 101a on the inner periphery of the end on the subject side (left side in FIG. 1), and moves in the optical axis direction, thereby moving the subject image incident from the zoom lens 101a. Change the magnification. The zoom lens 101a and the movable cylinder 102 are sealed so that foreign matters such as water and dust do not enter. The subject image incident from the zoom lens 101a forms an image on the image sensor 111 provided in the camera body 110 via the focus lens 101b. The focus lens 101b can be moved in the optical axis direction by a drive mechanism (not shown).

  A ring-shaped packing 108 is fitted to the subject side end of the outer peripheral portion 102 a of the movable cylinder 102. At the image surface side end of the outer peripheral portion 102a of the movable cylinder 102, three linearly moving keys 102b1 projecting radially outward are provided at substantially equal intervals in the circumferential direction. A cylindrical roller 102c1 is provided at the tip of each straight key 102b1.

  The guide tube 103 is slidably fitted to the cam ring 104 on the inner peripheral side of the cam ring 104 and is in contact with both ends of the cam ring 104 in the optical axis direction. Thereby, the guide cylinder 103 is rotatably supported in a state where movement in the radial direction and the optical axis direction is restricted with respect to the cam ring 104.

  The guide tube 103 is provided with three rectilinear grooves 103a1 extending in the optical axis direction at substantially equal intervals in the circumferential direction. The rectilinear groove 103a1 is formed so as to penetrate in the radial direction of the guide cylinder 103, and the rectilinear key 102b1 of the movable cylinder 102 is engaged with the rectilinear groove 103a1 so as to be movable in the optical axis direction. Thus, the guide tube 103 supports the movable tube 102 in the circumferential direction and the radial direction and supports the movable tube 102 so as to be movable in the optical axis direction.

  A flange portion 103a extending radially outward is provided at the end of the guide tube 103 on the subject side, and the surface of the flange portion 103a facing the image plane side moves the operation ring 106 toward the subject side in the optical axis direction. The contact surface 103b is regulated. The flange portion 103a is formed with three openings 103c1 penetrating in the optical axis direction at substantially equal intervals in the circumferential direction.

  Three cam grooves 104 a 1 that penetrate in the radial direction are formed in the cam ring 104 at substantially equal intervals in the circumferential direction corresponding to the rollers 102 c 1 of the movable cylinder 102. A roller 102c1 is cam-engaged with the cam groove 104a1. A gear portion 104b is formed on the outer peripheral portion of the image plane side end portion of the cam ring 104 over the entire circumference in the circumferential direction. The end surface on the image plane side of the cam ring 104 is disposed at the same position in the optical axis direction as a contact surface 105a (described later) of the fixed cylinder 105. Then, the cam action of the cam groove 104a1 of the cam ring 104 and the roller 102c1 of the movable cylinder 102 converts the rotation of the cam ring 104 into a straight movement in the optical axis direction of the movable cylinder 102.

  The fixed tube 105 is detachably fixed to the camera body 110 via the mount 105b, and the space between the fixed tube 105 and the camera body 110 is sealed so that foreign matter such as water and dust does not enter by an O-ring or the like. Has been. A guide cylinder 103 is fixed to the fixed cylinder 105, and an operation ring 106 is slidably fitted to the inner peripheral side of the fixed cylinder 105.

  The fixed cylinder 105 and the operation ring 106 are sealed with an O-ring or the like so that foreign matters such as water and dust do not enter. Further, the fixed cylinder 105 is provided with an abutting surface 105a composed of an annular surface that abuts the image plane side end surface of the operation ring 106 in the optical axis direction. Thereby, the fixed cylinder 105 rotatably supports the operation ring 106 in a state where the movement of the operation ring 106 on the image plane side in the optical axis direction is restricted.

  The operation ring 106 corresponds to an example of the operation unit of the present invention, and includes an operation convex portion 106e that protrudes radially outward at a central portion in the optical axis direction. The operation projection 106e is exposed to the outside between the fixed cylinder 105 and the front cover 107, and the operation ring 106 can be moved in the optical axis direction and rotated in the circumferential direction by a user operation. Here, the movement in the optical axis direction corresponds to an example of movement in the first direction of the present invention, and the rotation in the circumferential direction corresponds to an example of movement in the second direction of the present invention.

  At the image plane side end of the operation ring 106, a contact surface 106a formed of an annular surface capable of contacting the contact surface 105a of the fixed cylinder 105 in the optical axis direction is provided. In addition, a contact surface 106b formed of an annular surface capable of contacting with the contact surface 103b of the guide tube 103 and the optical axis direction is provided at the subject side end of the operation ring 106.

  Here, as shown in FIG. 1, when the contact surface 106 a of the operation ring 106 is in a position to contact the contact surface 105 a of the fixed cylinder 105, the contact surface 103 b of the guide cylinder 103 and the operation ring 106 are in contact with each other. Each contact surface is arranged so that the distance in the optical axis direction to the surface 106b is L2. Thereby, the amount of movement of the operation ring 106 in the optical axis direction with respect to the fixed cylinder 105 and the guide cylinder 103 is restricted within the range of the distance L2.

  A gear portion 106 c that meshes with the gear portion 104 b of the cam ring 104 is provided on the inner peripheral portion of the image plane side end portion of the operation ring 106. Both the gear part 106c and the gear part 104b are provided over the entire circumference in the range of the length L1 in the optical axis direction from the contact surface 106a. When the gear portion 106 c meshes with the gear portion 104 b, the rotational force of the operation ring 106 is transmitted to the cam ring 104, and the rotational force of the cam ring 104 is converted into a driving force in the optical axis direction of the movable cylinder 102. In addition, an annular yoke 106d made of a ferromagnetic material such as iron having a predetermined length in the optical axis direction is provided on the outer periphery of the object side end of the operation ring 106.

  The front cover 107 is formed in a substantially cylindrical shape, and is fitted and fixed to the flange portion 103 a of the guide tube 103. The front cover 107 has an abutment surface 107 a formed of an annular surface that is disposed on the subject side of the packing 108 fitted to the outer peripheral portion of the subject side end of the movable cylinder 102 and faces the packing 108 in the optical axis direction. Is provided. This restricts the movement of the packing 108 toward the subject in the optical axis direction. In the state shown in FIG. 1, the distance in the optical axis direction between the contact surface 107a of the front cover 107 and the pressing portion 109b of the pressing member 109 is set to d1.

  On the inner periphery of the front cover 107, a pressing member 109 is supported between the contact surface and the guide tube 103 so as to be movable in the optical axis direction. In addition, a magnet 107 b having magnetism is provided on the inner peripheral portion of the front cover 107. The magnet 107 b has a maximum radial facing area with the yoke 106 d provided on the operation ring 106 when the contact surface 106 b of the operation ring 106 contacts the contact surface 103 b of the guide tube 103. Has been placed.

  The packing 108 corresponds to an example of the elastic member of the present invention, and is formed of a ring-shaped member having a circular cross section having elasticity such as rubber. The inner diameter of the packing 108 in a free state is D0, and the cross-sectional diameter is d0. In this embodiment, since the inner diameter D0 of the packing 108 is smaller than the outer diameter D1 of the movable cylinder 102, the assembled packing 108 is elastically deformed so that the inner diameter becomes D1 by the outer peripheral portion 102a of the movable cylinder 102. .

  The distance d1 in the optical axis direction between the contact surface 107a of the front cover 107 and the pressing portion 109b of the pressing member 109 is smaller than the diameter d0 of the cross section of the packing 108. For this reason, the packing 108 in the assembled state is elastically deformed so that the thickness in the optical axis direction is d1 between the contact surface 107a and the pressing portion 109b. As a result, the pressing force in the direction away from each other in the optical axis direction acts between the front cover 107 and the pressing member 109 by the elastic force of the packing 108.

  A radially inner pressing force acting on the outer peripheral portion 102a of the movable cylinder 102 from the packing 108 is F1, and a pressing force on the subject side in the optical axis direction acting on the contact surface 107a of the front cover 107 from the packing 108. Is F2. Moreover, the packing 108 can increase or decrease the pressing force described above by further deforming the packing 108 against the elastic force.

  2A is a view of the pressing member 109 viewed from the image plane side in the optical axis direction, and FIG. 2B is a cross-sectional view taken along line AA of FIG. 2A.

  As shown in FIG. 2, the pressing member 109 is formed in an annular shape, and an opening 103 c 1 formed in the flange portion 103 a of the guide tube 103 is inserted into a surface facing the image surface side and extends to the image surface side. A pin 109a1 is formed. Three pins 109a1 are arranged at substantially equal intervals in the circumferential direction corresponding to the number of openings 103c1.

  The tip of the pin 109a1 faces the contact surface 106b of the operation ring 106 in the optical axis direction. Therefore, when the operation ring 106 is moved to the subject side in the optical axis direction, the pin 109a1 is pushed by the contact surface 106b. Thus, the pressing member 109 moves in the same direction. Further, in the state shown in FIG. 1, the tip of the pin 109a1 protrudes from the contact surface 103b of the guide tube 103 to the image surface side in the optical axis direction by L3.

  The surface of the pressing member 109 facing the subject is a pressing portion 109 b that faces the packing 108 in the optical axis direction, and the pressing portion 109 b is in contact with the packing 108. In addition, an annular convex contact portion 109c that protrudes toward the subject is provided radially opposite the packing 108 on the radially outer side of the contact portion of the pressing portion 109b with the packing 108.

  3 and 4 are cross-sectional views of the main part of the lens barrel 100a for explaining a deformed state of the packing 108 when the operation ring 106 is moved in the optical axis direction. Here, the distance between the contact surface 105a of the fixed cylinder 105 and the contact surface 106a of the operation ring 106 is x. Hereinafter, a deformation state of the packing 108 when the operation ring 106 is moved to the subject side in the optical axis direction and the distance x is gradually increased from 0 will be described.

  FIG. 3A shows a state of x = xa = 0 as in FIG. 1, and the contact surface 106 a of the operation ring 106 is in contact with the contact surface 105 a of the fixed cylinder 105. At this time, the gear portion 104 b of the cam ring 104 is engaged with the gear portion 106 c of the operation ring 106. Further, a radially inner pressing force F1 = F1a acting on the outer peripheral portion 102a of the movable cylinder 102 from the packing 108, and a subject in the optical axis direction acting on the contact surface 107a of the front cover 107 from the packing 108. The pressing force F2 to the side is F2a.

  FIG. 3B shows a state where x = xb = L2-L3, and the contact surface 106b of the operation ring 106 is in contact with the tip of the pin 109a1. At this time, in the present embodiment, since L1 <L2-L3 is set, the meshing between the gear portion 106c and the gear portion 104b is released. Further, the pressing force F1 = F1b and the pressing force F2 = F2b are satisfied, and F1b and F2b are the same as F1a and F2a, respectively. When the operation ring 106 is further moved to the subject side in the optical axis direction from the state of FIG. 3B, a pressing force in the same direction acts on the packing 108 via the pressing member 109, and FIG. It will be in the state shown.

  FIG. 4A shows a state where x = xc. In this state, the packing 108 is restricted from moving toward the subject side in the optical axis direction by the contact surface 107a of the front cover 107. Therefore, the packing 108 is moved in the optical axis direction by the contact portion 107a and the pressing portion 109b of the pressing member 109. Compressive deformation. Since the packing 108 is deformed so that the dimension w in the optical axis direction becomes small, the pressing force F2 becomes F2c larger than F2a.

  At the same time, the packing 108 is deformed so that the radial dimension h of the cross section increases and the inner diameter becomes smaller. However, since the inner diameter of the packing 108 is regulated by the outer peripheral portion 102a, the packing 108 is compressed in the radial direction. The pressing force F1 is F1c larger than F1a. In FIG. 4A, the outer diameter of the packing 108 is deformed so that the packing 108 is in contact with the contact portion 109c.

  FIG. 4B shows a state where x = xd = L2, and the contact surface 106b of the operation ring 106 is in contact with the contact surface 103b of the guide tube 103. At this time, the packing 108 abuts on the pressing portion 109b, the abutting surface 107a, the outer peripheral portion 102a, and the abutting portion 109c, and is compressed and deformed while being sandwiched in the radial direction and the axial direction.

  Since the outer diameter of the packing 108 is regulated by the contact portion 109c, the rate of increase of the pressing forces F1 and F2 accompanying the movement of the operation ring 106 in the optical axis direction is larger than that up to the state of FIG. . Further, the compressive deformation itself of the packing 108 becomes larger as compared with FIG. 4A, the pressing force F1 becomes F1d larger than F1c, and the pressing force F2 becomes F2d larger than F2c. F1c and F2c are set to values equal to or greater than the pressing force necessary to prevent the entry of foreign matters such as water and dust from the outside in a state where the movable cylinder 102 does not move in the optical axis direction.

  As the operation ring 106 moves in the optical axis direction, the opposing area in the radial direction between the yoke 106d and the magnet 107b changes. However, the opposing area is maximized in FIG. 4B, and the mutual magnetic attractive force is maximized. That is, the potential energy due to magnetism is minimized, and a holding force that holds the state of FIG. 4B is generated. This holding force prevents the pressing member 109 from moving to the image plane side in the optical axis direction by the elastic force of the packing 108, and the pressing forces F1 and F2 can be kept constant.

  FIG. 5A is a graph showing the relationship between the position in the optical axis direction of the operation ring 106 and the radially inner pressing force F <b> 1 acting on the outer peripheral portion 102 a of the movable cylinder 102 from the packing 108. FIG. 5B is a graph showing the relationship between the position of the operation ring 106 in the optical axis direction and the pressing force F2 from the packing 108 to the subject side in the optical axis direction acting on the contact surface 107a of the front cover 107. FIG.

  As described above, the length in the optical axis direction of the gear portion 106c of the operation ring 106 and the gear portion 104b of the cam ring 104 is L1, and when x = xa = 0 (see FIG. 3A), The contact surface 106a and the end surface on the image plane side of the cam ring 104 have the same position in the optical axis direction. Therefore, in the range of 0 ≦ x <L1, when the gear portion 106c and the gear portion 104b are engaged with each other and the operation ring 106 is rotated, the cam ring 104 is rotated and the movable cylinder 102 is moved in the optical axis direction. Can do. In the range of x ≧ L1, the meshing between the gear portion 106c and the gear portion 104b is released, and the movable cylinder 102 cannot be moved in the optical axis direction even if the operation ring 106 is rotated.

  Here, the state where the operation ring 106 is located in the range of 0 ≦ x <L1 (the range of ST1 in the figure) is defined as the first state. In the first state, the pressing force F1 is F1a (= F1b), and the pressing force F2 is F2a (= F2b).

  When the operation ring 106 is moved from the first state to the subject side in the optical axis direction, the contact surface 106b comes into contact with the pin 109a1 of the pressing member 109 (xb (FIG. 3B)), and light is applied to the packing 108. Axial compressive force acts. Thereafter, the pressing forces F1 and F2 increase (range xb to xc), and the packing 108 contacts the contact portion 109c (xc (FIG. 4A)). Thereafter, the increasing rates of the pressing forces F1 and F2 increase (range xc to xd), and the contact surface 106b of the operating ring 106 contacts the contact surface 103b of the guide tube 103 and stops.

  Here, in the present embodiment, in order to prevent foreign matter such as water and dust from entering between the packing 108 and the outer peripheral portion 102a of the movable cylinder 102 in a state where the movable cylinder 102 is not moved in the optical axis direction. A necessary pressing force F1 is set to Fp1. A distance x between the contact surface 105a of the fixed cylinder 105 and the contact surface 106a of the operation ring 106 when the pressing force F1 is Fp1 is defined as xp1.

  Further, a pressing force F2 necessary to prevent foreign matters such as water and dust from entering between the packing 108 and the contact surface 107a of the front cover 107 is defined as Fp2. A distance x between the contact surface 105a of the fixed cylinder 105 and the contact surface 106a of the operation ring 106 when the pressing force F2 is Fp2 is defined as xp2.

  In the present embodiment, in the range of x ≧ xp1, F1 ≧ Fp1 and F2> Fp2 are satisfied, so that the movable barrel 102 is not moved in the optical axis direction, so that the lens barrel 100a has water inside. And foreign matter such as dust can be prevented from entering.

  Further, the state where the operation ring 106 is located in the range of x ≧ xp1 (the range of ST2 in the figure) is set as the second state. In the second state, the meshing between the gear portion 106c and the gear portion 104b is released, and the movable cylinder 102 cannot be moved in the optical axis direction by the rotation operation of the operation ring 106.

  In the second state, the operation ring 106 is held so as not to move to the image plane side in the optical axis direction by the magnetic attractive force of the yoke 106d and the magnet 107b. If a force on the optical axis direction image plane side larger than the holding force is applied to the operation ring 106, the operation ring 106 can be returned to the first state.

  As described above, in the present embodiment, the first state in which the movable cylinder 102 can be moved in the optical axis direction, the movement of the movable cylinder 102 in the optical axis direction, and the pressing force of the packing 108 against the movable cylinder 102 are controlled. Can be switched to a second state greater than the first state. The operation ring 106 can deform the packing 108 via the pressing member 109 by movement in the optical axis direction, and can move the movable cylinder 102 in the optical axis direction by rotation. Further, the yoke 106d and the magnet 107b can generate a force that holds the pressing force of the packing 108 against the movable cylinder 102 in the second state.

  In particular, in the present embodiment, it is possible to switch whether or not the rotational force of the operation ring 106 is converted into the driving force in the optical axis direction of the movable cylinder 102 and transmitted by the movement of the operation ring 106 in the optical axis direction. .

  FIG. 6 is a flowchart illustrating an operation example of the digital still camera 100. In FIG. 6, in step S <b> 102, the user (photographer) determines whether or not the shooting location needs to be protected against foreign matters such as water and dust. If it is determined that protection is not necessary, after moving to the shooting location in step S103, the operation ring 106 is moved to the image plane side in the optical axis direction in step S104 to bring the lens barrel 100a into the first state. In this state, by rotating the operation ring 106 in step S105, the movable cylinder 102 is moved in the optical axis direction to perform a zoom operation to set a desired angle of view. Thereafter, shooting is performed in step S106, and the process ends.

  FIG. 7A is a cross-sectional view of a main part showing a state in which the movable cylinder 102 is extended toward the subject side in the optical axis direction in the first state. In the first state, the gear portion 106c and the gear portion 104b are engaged with each other, and the movable tube 102 can be moved in the optical axis direction by rotating the operation ring 106, and an arbitrary angle of view can be set by a zoom operation. .

  Further, since the pressing force F1 acting on the outer peripheral portion 102a of the movable cylinder 102 from the packing 108 is F1a smaller than the second state, the driving of the movable cylinder 102 by the frictional force between the packing 108 and the outer peripheral portion 102a. An increase in load can be prevented. Thereby, it is possible to avoid deterioration of the operational feeling when the user operates the operation ring 106, and to ensure good operability during zoom operation.

  In the first state, although the pressing force F1 is smaller than that in the second state, the pressing forces F1a and F2a act between the packing 108 and the outer peripheral portion 102a and between the packing 108 and the contact surface 107a. And sealed. For this reason, the effect which prevents that a foreign material penetrate | invades into the inside of the lens barrel 100a is acquired to some extent. For example, the target foreign matter may be water, and in the second state, the protection performance of the level of water proofing may be satisfied, and in the first state, the protection performance of the degree of drip proof lower than the life waterproofing may be satisfied.

  On the other hand, if it is determined in step S102 that protection is required, the operation ring 106 is moved to the image plane side in the optical axis direction in step S107, and the lens barrel 100a is set to the first state. Next, by rotating the operation ring 106 in step S108, the movable cylinder 102 is moved in the optical axis direction to perform a zoom operation, and a desired angle of view is set. Thereafter, in step S109, the operating ring 106 is moved to the subject side in the optical axis direction to place the lens barrel 100a in the second state. After moving to the shooting location in step S110, shooting is performed in step S111 and the process is terminated.

  FIG. 7B is a main part cross-sectional view showing a state in which the movable cylinder 102 is extended toward the subject side in the optical axis direction in the second state. In the second state, the meshing between the gear portion 106c and the gear portion 104b is released, and the movable cylinder 102 cannot be moved in the optical axis direction by the rotation operation of the operation ring 106. Therefore, there is no possibility that the movable cylinder 102 is erroneously retracted and the foreign matter W adhering to the outer peripheral portion 102a is carried into the lens barrel 100a as the movable cylinder 102 moves. As a result, it is possible to reliably prevent entry of foreign matter.

  Further, the pressing force F1 acting on the outer peripheral portion 102a of the movable cylinder 102 from the packing 108 is larger than the pressing force Fp1 necessary for preventing the intrusion of foreign matter in a state where the movable cylinder 102 is not moving in the optical axis direction. F1d. Further, the pressing force F2 that acts on the contact surface 107a of the front cover 107 from the packing 108 is F2d that is larger than the pressing force Fp2 that is necessary to prevent the entry of foreign matter. As a result, it is possible to improve the degree of protection against the intrusion of foreign matter with respect to the first state and reliably prevent the intrusion of foreign matter.

  Further, the operating ring 106 does not move to the image plane side in the optical axis direction due to the magnetic attractive force between the yoke 106d and the magnet 107b, and the pressing force of the packing 108 is kept constant. Intrusion can be prevented. In addition, since it is possible to switch to the second state after performing a zoom operation by operating the operation ring 106, it is possible to prevent foreign matter from entering the lens barrel 100a at an arbitrary angle of view.

  As described above, in the present embodiment, the zoom operation, the switching of the zoom operation and the switching to the extent that the lens barrel 100a is protected from the intrusion of the foreign object can be performed by a series of mechanisms linked to the operation of the operation ring 106. It is possible to prevent the mechanism from becoming large and complicated. In addition, since the zoom operation, the switching of whether or not the zoom operation can be performed, and the switching that protects against the intrusion of a foreign object can be performed only by operating the operation ring 106, the operation unit does not change and the operability is good.

  As described above, in the present embodiment, the seal of the lens barrel 100a is achieved while reducing the size and cost of the digital still camera 100 without increasing the driving load of the movable barrel 102 of the lens barrel 100a. Can be improved.

  Note that the present invention is not limited to the above-described embodiment, and for example, a focusing operation that changes the focus of an image formed on the image sensor 111 may be possible by moving the movable cylinder in the optical axis direction. The lens barrel 100a may be retractable when the lens barrel 100a is miniaturized. Further, the zoom lens 101a may be a finder eyepiece, and the diopter adjustment may be performed by moving the movable cylinder in the optical axis direction. Further, the lens barrel 100a and the camera main body 110 may be integrated to eliminate the gap between the mount 105b and the camera main body 110, thereby further strengthening the entry of foreign matter.

  In addition, the cross section of the packing 108 is not circular, but is changed to a U-shaped cross section, an X-shaped cross section, a cross section with a lip portion, etc. to improve the protection performance according to the assumed foreign matter, and improve the assemblability. Or you may. Further, the packing 108 and the movable cylinder 102 may be separated from each other in the first state to eliminate the friction load, and the driving load may be reduced by reducing the resistance of air flowing inside and outside the digital still camera 100.

  Further, the yoke 106d and the magnet 107b may be arranged so as to face each other in the optical axis direction, and instead of the magnetic attraction force, the frictional force between the members having a large friction coefficient is used in the optical axis direction of the operation ring 106. Movement to the image plane side may be restricted. Further, a so-called bayonet mechanism may be provided on the operation ring 106 and the front cover 107, and the operation ring 106 may be rotated in the second state to restrict movement toward the image plane in the optical axis direction.

  Further, the operation ring 106 may be moved to the image plane side in the optical axis direction to switch to the second state. Further, an operation actuator 106 may be electrically driven by adding an actuator. In that case, a control circuit provided in the camera body 110 can be provided, and the operation ring 106 can be moved or rotated in the optical axis direction in conjunction with an external mechanical switch or various photographing operations. In the first state, it is possible to prevent the driving load from increasing due to the frictional force between the packing 108 and the movable cylinder 102, and to reduce the power consumption during electric driving.

(Second Embodiment)
FIG. 8 is a schematic cross-sectional view along the optical axis direction of a digital still camera as an example of an imaging apparatus including a lens barrel that is the second embodiment of the present invention. In the present embodiment, only different parts from the first embodiment will be described, and description of overlapping parts will be omitted.

  As shown in FIG. 8, in the digital still camera 200 of the present embodiment, a gear portion 204b is provided along the circumferential direction over a range of a predetermined length in the optical axis direction on the inner peripheral portion of the image plane side end portion of the cam ring 204. Provided. The operation ring 206 is provided with a light shielding portion 206c extending from the contact surface 206a on the image surface side with the fixed cylinder 205 to the image surface side in the optical axis direction. A plurality of light-shielding portions 206 are provided at substantially equal intervals in the circumferential direction and arranged in a comb shape, and the light transmittance in the radial direction is low. The interval between the light shielding portions 206c in the circumferential direction is P, and the width of each light shielding portion 206c in the circumferential direction is P / 2.

  A driving unit 212 made of a stepping motor or the like is fixed to the fixed cylinder 205. A pinion 212a is fixed to the drive shaft of the drive unit 212. The pinion 212a is rotated in the forward and reverse directions around a rotation axis parallel to the optical axis direction by controlling the drive unit 212 with a control circuit (not shown). Is possible. Further, the pinion 212a meshes with the gear portion 204b. Therefore, the rotation of the pinion 212a is transmitted to the cam ring 204 via the gear portion 204b by driving the drive portion 212, and the cam ring 204 can be rotated. it can.

  Further, sensors 213 and 214 made of a photo interrupter or the like are fixed to the fixed cylinder 205. The sensors 213 and 214 have a substantially U-shaped cross section with a constant width in the circumferential direction, and include slits 213a and 214a that open on the subject side in the optical axis direction and penetrate in the circumferential direction. The sensors 213 and 214 have a light emitting part and a light receiving part, detect the amount of light passing through the slits 213a and 214a in the radial direction, and output a detection signal to a control circuit (not shown). When the contact surface 205a of the fixed cylinder 205 is in contact with the contact surface 206a of the operation ring 206, the light shielding portion 206c is inserted into the slits 213a and 214a by the dimension L1 in the optical axis direction.

  FIG. 9A is a partial development view showing the relationship between the light shielding portion 206c and the sensors 213 and 214 in a state where the contact surface 205a of the fixed cylinder 205 and the contact surface 206a of the operation ring 206 are in contact. .

  In the state of FIG. 9A, when any one of the light shielding portions 206c passes through the slit 213a or the slit 214a in the circumferential direction, the amount of light passing in the radial direction changes and is output as a detection signal of one cycle. When the operation ring 206 rotates, the light-shielding portion 206c sequentially passes through the slit 213a and the slit 214a, and a detection signal having a period corresponding to the rotation speed is output.

  In addition, the light shielding portions 206c are arranged at regular intervals P in the circumferential direction, while the sensors 213 and 214 are arranged so that the circumferential distance between the centerlines of each other is (2 + 1/4) × P. Therefore, the detection signals output from the sensor 213 and the sensor 214 are different in phase by ¼ period, and the rotation direction of the operation ring 206 can be calculated. The circumferential distance between the center lines of the sensor 213 and the sensor 214 is not limited to (2 + 1/4) × P, and may be (N + 1/4) × P where N is zero or a natural number other than 2.

  In FIG. 9B, the operation ring 206 moves to the subject side in the optical axis direction, and the light is shielded when the distance between the contact surface 205a of the fixed cylinder 205 and the contact surface 206a of the operation ring 206 is L2-L3. FIG. 6 is a partial development view showing a relationship between a portion 206c and sensors 213 and 214. This is a case equivalent to FIG. 3B of the first embodiment.

  In the present embodiment, since L1 <L2-L3 is set, the light shielding portion 206c is not inserted in the optical axis direction inside the slits 213a and 214a. At this time, even if the operation ring 206 rotates, the light shielding portion 206c does not pass through the slit 213a and the slit 214a, and no detection signal is output.

  A control circuit (not shown) can calculate the rotation speed and the rotation direction of the operation ring 206 based on the detection signals output from the sensors 213 and 214. Further, the control circuit can output a drive signal to the drive unit 212 based on the calculated rotation speed and rotation direction of the operation ring 206.

  If the distance between the contact surface 205a of the fixed cylinder 205 and the contact surface 206a of the operation ring 206 is x, the light shielding portion 206c is inserted into the slits 213a and 214a within the range of 0 ≦ x <L1, and the sensor 213 , 214 outputs a detection signal. The control circuit outputs a drive signal to the drive unit 212 based on the detection signals from the sensors 213 and 214. Thereby, the cam ring 204 rotates via the pinion 212a, and the movable cylinder 202 moves in the optical axis direction.

  On the other hand, in the range of x ≧ L1, the light shielding portion 206c is not inserted into the slits 213a and 214a, and no detection signal is output from the sensors 213 and 214. Therefore, no drive signal is output from the control circuit, and the movable cylinder 202 does not move in the optical axis direction. A state in which the operation ring 206 is located in a range of 0 ≦ x <L1 is defined as a first state.

  As described above, in the present embodiment, the sensors 213 and 214 can detect that the user has moved the operation ring 206 in the optical axis direction. Further, based on the outputs of the sensors 213 and 214, it is possible to switch whether or not the movable portion 202 can be moved in the optical axis direction by the driving unit 212. Other configurations and operational effects are the same as those in the first embodiment.

  In addition, as a means for detecting the movement of the operation ring 206 in the optical axis direction, a magnetic sensor, an electric resistance, a mechanical switch, or the like may be used instead of an optical sensor such as a photo interrupter. Further, a sensor for detecting the movement of the operation ring 206 in the optical axis direction and a sensor for detecting the rotation of the operation ring 206 may be provided separately to optimize each detection accuracy.

(Third embodiment)
FIG. 10 is a schematic cross-sectional view along the optical axis direction of a digital still camera as an example of an imaging apparatus including a lens barrel that is the third embodiment of the present invention. In the present embodiment, only different parts from the first embodiment will be described, and description of overlapping parts will be omitted.

  As shown in FIG. 10, the digital still camera 300 according to the present embodiment has a circumferential direction over the range of the optical axis direction length L4 from the image surface side end surface to the subject side at the outer periphery of the image surface side end of the cam ring 304. A gear portion 304b is provided along the entire circumference. A gear portion 306c is provided along the entire circumference in the circumferential direction over the range of the length L4 in the optical axis direction from the contact surface 306a of the end surface on the image surface side to the subject side on the inner peripheral portion of the image surface side end portion of the operation ring 306. It is done. The gear portion 306c meshes with the gear portion 304b. Therefore, the rotation of the operation ring 306 is transmitted to the cam ring 304 via the gear portion 306c and the gear portion 304b, and the cam ring 304 can be rotated.

  In this embodiment, the length L4 of the gear portions 304b and 306c in the optical axis direction is the movement of the operation ring 306 in the optical axis direction regulated by the contact surface 303b of the guide tube 303 and the contact surface 305a of the fixed tube 305. Compared with the range L2, there is a relationship of L4> L2. Accordingly, the meshing state of the gear portion 306c and the gear portion 304b is maintained regardless of the position of the operation ring 306 in the optical axis direction.

  The guide tube 303 is provided with a convex portion 303d extending toward the image surface side in the optical axis direction at a radially outer position of the contact surface 303b with which the contact surface 306b of the object side end surface of the operation ring 306 can contact. A plurality of convex portions 303d are provided at substantially equal intervals in the circumferential direction and are arranged in a comb shape. With the contact surface 306a on the image plane side of the operation ring 306 in contact with the contact surface 305a of the fixed cylinder 305, the optical axis between the convex portion 303d of the guide cylinder and the contact surface 306b on the subject side of the operation ring 306 The distance in the direction is L1.

  On the outer peripheral side of the contact surface 306b of the operation ring 306, a plurality of concave portions 306d corresponding to the plurality of convex portions 303d are provided at substantially equal intervals in the circumferential direction. The concave portion 306d is formed at the same radial position as the convex portion 303d, and the convex portion 303d can be inserted in the optical axis direction so as to face the convex portion 303d in the optical axis direction.

  FIG. 11A is a partial development view showing the relationship between the convex portion 303d and the concave portion 306d in a state where the contact surface 306a of the operation ring 306 is in contact with the contact surface 305a of the fixed cylinder 305. FIG.

  As shown in FIG. 11A, the circumferential interval between the plurality of convex portions 303d is P, and the circumferential width of the convex portion 303d is P / 2. Chamfering is performed on both sides of the tip of the convex portion 303d. Further, the circumferential interval between the plurality of recesses 306d is P, and the circumferential width of the recesses 306d is P / 2. Chamfering is performed on both sides of the insertion opening of the convex portion 303d of the concave portion 306d. In the state of FIG. 11A, the convex portion 303d and the concave portion 306d are separated from each other in the optical axis direction, so that the operation ring 306 can be rotated.

  FIG. 11B shows a state in which the operation ring 306 has moved from the state of FIG. 11A toward the subject side in the optical axis direction and is in contact with the packing 108 and the contact portion 309c of the pressing member 309 (the first embodiment described above). FIG. 5 is a partial development view in the same manner as in FIG.

  In the state of FIG. 11B, when the convex portion 303d is inserted into the concave portion 306d in the optical axis direction and the operation ring 306 is to be rotated, the convex portion 303d and the concave portion 306d abut on each other in the circumferential direction. Rotation is regulated.

  If the distance between the contact surface 305a of the fixed cylinder 305 and the contact surface 306a of the operation ring 306 is x, the convex portion 303d and the concave portion 306d are separated in the optical axis direction within the range of 0 ≦ x ≦ L1, and the operation The ring 306 can be rotated. By rotating the operation ring 306, the movable ring 302 can be moved in the optical axis direction by rotating the cam ring 304 via the gear portion 306c and the gear portion 304b. A state in which the operation ring 306 is located in the range of 0 ≦ x ≦ L1 is defined as a first state.

  On the other hand, in the range of x> L1, the convex portion 303d is inserted into the concave portion 306d in the optical axis direction, and the rotation of the operation ring 306 is restricted. Therefore, the cam ring 304 cannot be rotated, and the movable cylinder 302 cannot be moved in the optical axis direction. Referring to FIG. 5, in the second state (ST2 in the figure), x> L1 is satisfied. That is, in the second state, the convex portion 303d is inserted into the concave portion 306d in the optical axis direction, the rotation of the operation ring 306 is restricted, and the movable cylinder 302 cannot be moved in the optical axis direction.

  As described above, in the present embodiment, the rotation of the operation ring 306 is restricted in the second state, and the movement of the movable cylinder 302 in the optical axis direction when the gear portion 306c and the gear portion 304b are engaged is prevented. be able to. Other configurations and operational effects are the same as those in the first embodiment.

  The present invention is not limited to the above-described embodiment. For example, as a means for restricting the rotation of the operation ring 306, a restricting means using a frictional force such as pressing a member such as rubber having a high friction coefficient may be used.

DESCRIPTION OF SYMBOLS 100 Digital still camera 100a Lens barrel 101a Zoom lens 102 Movable cylinder 103 Guide cylinder 104 Cam ring 105 Fixed cylinder 106 Operation ring 107 Front cover 108 Packing 109 Press member 110 Camera body 111 Imaging element

Claims (7)

A movable cylinder movable in the optical axis direction;
An elastic member that applies a pressing force to seal the outer peripheral portion against the outer peripheral portion of the movable cylinder by elastic deformation;
An operation unit which is movable in a first direction and a second direction different from the first direction, and moves the movable cylinder in the optical axis direction via a transmission means by movement in the second direction;
A first state that enables movement of the movable cylinder in the optical axis direction by movement of the operation section in the second direction; and movement of the movable cylinder in the optical axis direction by movement of the operation section in the second direction. In addition to being restricted, the elastic member can be further elastically deformed to switch the second state in which the pressing force is larger than the first state by moving the operation unit in the first direction. A lens barrel.   The lens barrel according to claim 1, further comprising a holding unit that holds the pressing force in the second state.   The lens barrel according to claim 1, wherein the transmission unit includes a driving unit that generates a driving force for moving the movable tube in the optical axis direction. Detecting means for detecting movement of the operation unit in the first direction;
4. The lens barrel according to claim 3, wherein whether or not the movable portion can be moved in the optical axis direction by the drive unit can be switched based on the output of the detection means. 5.   The lens barrel according to claim 1, further comprising a restricting unit that restricts movement of the operation unit in the second direction in the second state.   The lens barrel according to claim 1, wherein the movable barrel holds a zoom lens.   An imaging apparatus comprising the lens barrel according to claim 1.

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