JP5333543B2 - Lens barrel and imaging device - Google Patents

Description

  The present invention relates to a lens barrel and an imaging apparatus.

Patent Document 1 below discloses a zoom lens configured to move in the optical axis direction by a zooming operation and also move in the optical axis direction by a focusing operation.
JP-A-5-142475

  In the conventional zoom lens, when the holding frame that holds the optical system is formed so as to engage and move with the guide shaft, the holding frame of the optical system cannot be rotated by the focusing operation. There were restrictions.

Therefore, in order to solve the above problem, as a first aspect of the present invention, the shaft-shaped guide shaft (192) supported with respect to the reference member (110) and the optical system (L2) are held, and the reference is also made. A holding member (180) provided so as to be movable in the axial direction of the guide shaft with respect to the member, and an engaging portion (174) engaged with the holding member, and guiding while rotating around the optical axis of the optical system And an interlocking member (170) that moves along the guide shaft without rotating the holding member by moving in the direction of the shaft, and the holding member extends along the circumferential direction centering on the optical axis of the optical system. The interlocking member has, as an engaging portion, a protrusion (187) that engages with the groove of the holding member, and the engaging portion is positioned near the guide shaft. Alternatively, the lens barrel (1) is engaged at a position on the extension line. 0) is provided.

  According to a second aspect of the present invention, the imaging apparatus includes the lens barrel (100) and an imaging unit (200) that captures an image formed using the lens barrel. (300) is provided.

  Furthermore, a sub-combination of the above feature groups can also be an invention.

  Hereinafter, the present invention will be described through embodiments of the invention. However, the following embodiments do not limit the invention according to the claims. In addition, not all the combinations of features described in the embodiments are essential for the solving means of the invention.

  FIG. 1 is a cross-sectional view of the entire lens barrel 100, showing a state in which the lens barrel 100 is at the wide-angle end. The lens barrel 100 includes five groups of lenses L1, L2, L3, L4, and L5 arranged on a common optical axis X.

  In the zoom operation of the lens barrel 100, the lenses L1, L2, L3, L4, and L5 move relatively. However, the pair of lenses L3 and L5 are connected to each other and move integrally with a certain distance. On the other hand, in the focusing operation of the lens barrel 100, the specific lens L2 moves, and the other lenses L1, L3, L4, and L5 do not move. That is, the lens L2 moves both in the zoom operation and in the focusing operation.

  However, the lens L2 moves relatively large in relation to the other lenses L1, L3, L4, and L5 in the zoom operation, but the movement amount is small in the focusing operation. Hereinafter, a structure responsible for the zoom operation of the lenses L1 and L2 and a structure responsible for the focusing operation of the lens L2 will be described. The description of the support structure and drive structure of the other lenses L3, L4, and L5 is omitted.

  The lens barrel 100 includes a pair of guide bars 192 and 194 disposed inside the fixed barrel 110 and a holding barrel 180. The lens L2 is held by a lens frame 189 formed at the tip (left side in the drawing) of the holding cylinder 180.

  The pair of guide bars 192 and 194 are arranged to face each other across the optical axis. One guide bar 192 is supported by a pair of support portions 118 disposed on the upper inner surface of the fixed cylinder 110.

  The holding cylinder 180 has a front side fitting part 181 and a rear side fitting part 183 that are arranged at intervals in the extending direction of the guide bar 192. Each of the front fitting portion 181 and the rear fitting portion 183 has a fitting hole having a shape complementary to the outer peripheral surface of the guide bar 192. For example, when the cross section of the guide bar 192 is circular, the fitting hole is a round hole. The guide bar 192 is inserted through the fitting hole. As a result, the holding cylinder 180 is suspended from the guide bar 192. Since the front fitting portion 181 and the rear fitting portion 183 that are separated from each other are engaged with the guide bar 192, the optical axis of the lens L1 is prevented from being inclined with respect to the guide bar 192.

  The other guide bar 194 is supported in parallel with the guide bar 192 by a pair of support portions 119 arranged on the lower side of the inner surface of the fixed cylinder 110. The holding cylinder 180 has an engaging portion 185 disposed on the opposite side across the optical axis between the front fitting portion 181 and the rear fitting portion 183 in the extending direction of the guide bar 192.

  The engaging portion 185 engages with the guide bar 194 through a pair of parallel surfaces that sandwich the guide bar 194. The pair of parallel surfaces are formed by long holes or U-shaped grooves. Accordingly, the holding cylinder 180 is prevented from rotating around the guide bar 192 while reducing the sliding resistance of the holding cylinder 180 moving along the guide bar 194.

  Inside the fixed cylinder 110, there is a cam cylinder 160 arranged coaxially with the fixed cylinder 110 and between the inner surface of the fixed cylinder 110 and the guide bars 192 and 194. The cam cylinder 160 will be described later.

  A cavity forming the motor chamber 115 is formed on the outer periphery of the rear side (right side in the drawing) of the fixed cylinder 110. A motor (not shown) is accommodated in the motor chamber 115. A focus ring 120 is rotatably mounted on the outer periphery of the motor chamber 115.

  One end of the transmission member 122 appears inside the motor chamber 115, and either the focus ring 120 or the motor selectively drives the transmission member 122. The driven transmission member 122 rotates around the optical axis X along the outer periphery of the fixed cylinder 110.

  On the front end side of the fixed cylinder 110, an inner cylinder 144, an intermediate cylinder 140, and an outer cylinder 150 are coaxially arranged in this order from the inside. A zoom ring 130 is rotatably mounted on the outer side of the outer cylinder 150. A lens frame 159 is formed at the front end of the outer cylinder 150 to hold the lens L1. A cam follower 152 is formed near the rear end of the outer cylinder 150 and engages with the inner cylinder 144.

  A guide groove 132 is formed inside the zoom ring 130. The cam follower 142 of the middle cylinder 140 is engaged with the guide groove 132. Thereby, when the zoom ring 130 rotates, the rotational driving force is transmitted to the cam follower 142.

  The middle cylinder 140 has the cam follower 142 and the cam groove 146. Further, the middle cylinder 140 has an engaging portion 148 that engages with the inner cylinder 144. The inner cylinder 144 has a cam groove 145 corresponding to the cam groove 146. Further, the inner cylinder 144 has a cam pin 149.

  The rear end of the inner cylinder 144 is guided by the guide portion 114 of the fixed cylinder 110, and the inner cylinder 144 advances and retreats. On the other hand, when the cam follower 142 of the middle cylinder 140 receives a rotational driving force, the middle cylinder 140 and the inner cylinder 144 cooperate to transmit the drive to the cam follower 152 in a straight line.

  The cam cylinder 160 has cam grooves 161 and 166. Further, the cam cylinder 160 has a cam follower 162. The cam pin 149 of the inner cylinder 144 is engaged with the cam groove 166. The cam follower 162 is engaged with the cam groove 146 of the middle cylinder 140 and the cam groove 145 of the inner cylinder 144.

  Further, the lens barrel 100 includes an interlocking tube 170 disposed at the front end of the fixed tube 110 over the inside and outside of the fixed tube 110. The interlocking cylinder 170 is disposed so as to be rotatable around the optical axis X along the inner side of the inner cylinder 144. A straight groove 176 extending in the optical axis X direction is formed on the outer peripheral surface of the interlocking cylinder 170. The straight groove 176 engages with the distal end portion 124 of the transmission member 122.

  The interlocking cylinder 170 has a circumferential groove 174 formed on the inner circumferential surface front side. The circumferential groove 174 is formed continuously in the circumferential direction, and engages with an engagement pin 187 that projects from the holding cylinder 180 in the radial direction. The interlocking cylinder 170 has a cam follower 172 that engages with the cam groove 161 of the cam cylinder 160.

  The fixed cylinder 110 is coupled to an imaging unit 200 described later by a base 112 formed at the rear end that is the right end in the drawing. When coupled to the imaging unit 200, the mounting surface 113 on the rear end surface of the fixed cylinder 110 is in close contact with the front surface of the imaging unit 200, so that the entire lens barrel 100 is positioned.

  When the focus ring 120 is rotated in the lens barrel 100 having the above-described structure, or when the transmission member 122 is driven by a motor, the transmission member 122 transmits light along the outer peripheral surface of the fixed tube 110. Rotate around axis X. The rotational driving force of the transmission member 122 is transmitted to the interlocking cylinder 170 through the side wall of the straight groove 176.

  As the interlocking cylinder 170 rotates in the circumferential direction, the cam follower 172 provided in the interlocking cylinder 170 rotates in the circumferential direction. At this time, since the cam follower 172 is engaged with the cam groove 161, the cam follower 172 moves in the optical axis X direction along the cam groove 161, and displaces the interlocking cylinder 170 in the optical axis X direction. The movement of the interlocking cylinder 170 in the optical axis X direction is transmitted to the holding cylinder 180 by the contact between the rear end surface of the circumferential groove 174 and the engaging pin 187.

  The holding cylinder 180 is restrained from displacement in the circumferential direction by the guide bars 192 and 194 and does not rotate. Further, since the circumferential groove 174 is continuously formed in the circumferential direction, the rotation of the interlocking cylinder 170 around the optical axis X causes the rear end surface of the circumferential groove 174 to slide in the circumferential direction with respect to the engagement pin 187. Therefore, the signal is not transmitted to the holding cylinder 180. Thereby, the lens L2 moves in the optical axis X direction without rotating in the circumferential direction, and focuses the optical system of the lens barrel 100. Further, these series of focusing operations are completed without moving the other lenses L1, L3, L4, and L5 at all.

  FIG. 2 is a longitudinal sectional view of the lens barrel 100 and shows a state in which the lens barrel 100 is zoomed to the telephoto end. Elements that are the same as those in FIG. 1 are denoted by the same reference numerals, and redundant description is omitted.

  When the zoom ring 130 is operated from the outside and rotated around the optical axis X, the cam follower 142 of the middle cylinder 140 is engaged with the guide groove 132 of the zoom ring 130, so that a rotational driving force is applied to the middle cylinder 140. Communicated. The inner cylinder 144 is guided in the guide portion 114 of the fixed cylinder 110 at the rear end thereof and moves in the optical axis direction.

  As the inner cylinder 144 moves in the optical axis direction, the middle cylinder 140 engaged with the inner cylinder 144 by the engaging portion 148 also moves, and thereby the cam follower 152 of the outer cylinder 150 engaged with the middle cylinder 140 is moved. Move forward. Therefore, the outer cylinder 150 is fed forward (left side in the figure), and the lens L1 held by the outer cylinder 150 is also fed forward.

  The middle cylinder 140 rotates the cam cylinder 160 around the optical axis X via the cam follower 162. Further, due to the engagement between the cam pin 149 and the cam groove 166, the cam cylinder 160 moves in the optical axis X direction. On the other hand, since the leading end 124 of the transmission member 122 enters the straight groove 176 of the interlocking cylinder 170, the interlocking cylinder 170 moves without rotating. Therefore, the interlocking cylinder 170 in which the cam follower 172 is engaged with the cam groove 161 of the cam cylinder 160 moves in the optical axis X direction as the cam cylinder 160 rotates and moves.

  Since the circumferential groove 174 of the interlocking cylinder 170 is engaged with the engagement pin 187 of the holding cylinder 180, when the interlocking cylinder 170 moves in the optical axis X direction, a driving force that travels straight is transmitted to cause the holding cylinder 180 to move. It moves integrally with the interlocking cylinder 170.

  In the present embodiment, a circumferential groove 174 is provided in the interlocking cylinder 170, and an engagement pin 187 is provided in the holding cylinder 180. However, the engagement structure of the interlocking cylinder 170 and the holding cylinder 180 is not limited to this. Even if the peripheral groove 174 is provided on the holding cylinder 180 side and the engaging pin 187 is provided on the interlocking cylinder 170 side, the engaging cylinder 170 is engaged. Good.

  Further, the circumferential groove 174 does not have to draw a complete circumference. That is, it is sufficient to draw an arc larger than the rotation angle of the focus ring 120 and the interlocking cylinder 170. Thereby, the manufacturing amount of the lens barrel 100 can be reduced by reducing the processing amount of the interlocking barrel 170 and the like.

  Furthermore, the circumferential groove 174 of the interlocking cylinder 170 may be formed as a cam groove that intersects with a plane orthogonal to the optical axis X. Accordingly, when the interlocking cylinder 170 rotates with respect to the holding cylinder 180, the holding cylinder 180 can be individually driven in the optical axis X direction. Accordingly, it is possible to correct a focus adjustment error caused by moving on a zooming cam during focusing.

  Since the cam follower 172 of the interlocking cylinder 170 is engaged with the cam groove 161 of the cam cylinder 160, the cam groove 161 moves the cam follower 172 when the cam cylinder 160 moves in the optical axis X direction and when the cam cylinder 160 rotates. In either case, the driving force parallel to the optical axis X is transmitted to the holding cylinder 180. In this case, since the holding cylinder 180 is engaged with the guide bar 192 and engaged with the guide bar 194, the holding cylinder 180 can be moved without tilting the lens L2 in a direction parallel to the optical axis X.

  Although not shown, the other lenses L3, L4, and L5 may be moved by other cam grooves 164 provided in the cam cylinder 160. Further, the other lenses L3, L4, L5 and the guide bars 192, 194 can be shared. Furthermore, other guide members and drive members may be provided for the purpose of guiding the other lenses L3, L4, and L5. As a result, all of the lenses L1, L2, L3, L4, and L5 move, and the focal length of the optical system of the lens barrel 100 changes.

  A cover cylinder 155 that is mounted coaxially with respect to the fixed cylinder 110 is disposed between the outer cylinder 150 and the zoom ring 130. The cover cylinder 155 advances and retreats along with the outer cylinder 150, and seals between the outer cylinder 150 and the zoom ring 130. This prevents dust from entering the lens barrel 100.

  In addition, the fixed cylinder 110 is coupled to an imaging unit 200 described later by a base 112 formed at the rear end that is the right end in the drawing. When coupled to the imaging unit 200, the mounting surface 113 on the rear end surface of the fixed cylinder 110 is in close contact with the front surface of the imaging unit 200, so that the entire lens barrel 100 is positioned.

  As described above, according to the embodiment shown in FIGS. 1 and 2, the lens barrel 100 is engaged with the holding cylinder 180 that holds the lens L2 so as to be rotatable about the optical axis X of the lens L2. Is provided. The interlocking cylinder 170 moves the lens L <b> 2 in the direction of the optical axis X by the rotational driving force transmitted from the zoom ring 130 via the cam cylinder 160 in the zoom operation. The interlocking cylinder 170 moves the lens L2 in the optical axis X direction by the rotational force transmitted from the focus ring 120 or the motor via the transmission member 122 in the focusing operation.

  The holding cylinder 180 is guided by the guide bars 192 and 194 and moves only in the optical axis X direction. Accordingly, it is possible to perform the zoom operation and the focusing operation while reducing the number of parts that may cause a mechanical error.

  From the viewpoint of efficiently transmitting the driving force and reducing the operating force of the holding cylinder 180, the cam follower 172 that drives the interlocking cylinder 170 is preferably disposed on the extension line of the guide bar 192 or in the vicinity thereof. Thereby, the position where the driving force is applied and the position of the guide bar 192 serving as a load resistance to the position can be brought close to each other, and the lens L2 can be effectively prevented from being inclined.

  3 and 4 are cross-sectional views showing the structure of the lens barrel 101 having another structure. FIG. 3 shows a state where the lens barrel 101 is at the wide-angle end. FIG. 4 shows a state in which the lens barrel 101 is changed to the telephoto end by the zoom operation.

  Furthermore, the lens barrel 101 has the same structure as the lens barrel 100 shown in FIGS. 1 and 2 except for the portions described below. Therefore, common elements are denoted by the same reference numerals, and redundant description is omitted.

  One feature of the lens barrel 101 is that guide bars 192 and 194 are coupled to the holding cylinder 180 and move together with the holding cylinder 180 in a direction parallel to the optical axis X. That is, the guide bars 192 and 194 are coupled to the holding cylinder 180 at their front ends (left side in the drawing).

  One guide bar 192 is supported by the front fitting part 116 and the rear fitting part 117 formed on the inner surface of the fixed cylinder 110. Here, the front side fitting part 116 and the rear side fitting part 117 have an insertion hole having a complementary shape on the peripheral surface of the guide bar 192, and the guide bar 192 is inserted therethrough. Thereby, the fixed cylinder 110 is suspended via the guide bar 192 so as to be movable in a direction parallel to the optical axis X.

  The other guide bar 194 is supported by the engaging portion 111 arranged at the lower part of the inner surface of the fixed cylinder. The engaging portion 111 is engaged with the guide bar 194 by a pair of parallel surfaces sandwiching the guide bar 194.

  In such a lens barrel 101, the holding barrel 180 can be formed shorter than the lens barrel 100. Further, since there is no rear end portion of the holding cylinder 180, in particular, a portion for holding the guide bars 192 and 194, an internal space of the fixed cylinder 110 is made empty. Thereby, the lens barrel 101 can be made thinner, or more members can be used in the lens barrel 101.

  FIG. 5 is a diagram schematically illustrating the structure of the imaging apparatus 300 including the lens barrel 100. In FIG. 5, the lens barrel 100 is schematically illustrated for the purpose of avoiding complicated drawing. However, the lens barrel 100 in FIG. 5 has the same structure as the lens barrel 100 shown in FIG. Therefore, the same components are denoted by the same reference numerals, and redundant description is omitted.

  The lens barrel 100 is detachably attached to the imaging unit 200 via the mount unit 260. In the imaging apparatus 300, the lens barrel 100 and the imaging unit 200 are also electrically coupled via a connection terminal (not shown). Thereby, the lens barrel 100 is supplied with power from the imaging unit 200.

  The imaging unit 200 houses an optical system including a main mirror 240, a pentaprism 270, and an eyepiece optical system 290, and a main control unit 250. The primary mirror 240 has a standby position that is inclined on the optical path of incident light incident through the optical system of the lens barrel 100, and an imaging position that rises while avoiding the incident light (indicated by a dotted line in the figure). Move between.

  The primary mirror 240 in the standby position guides most of the incident light to the focusing screen 272 disposed above. The focusing screen 272 is disposed at a focus position of the optical system of the lens barrel 100 and forms an image formed by the optical system.

  The image formed on the focusing screen 272 is observed from the eyepiece optical system 290 via the pentaprism 270. As a result, the image on the focusing screen 272 can be viewed as a normal image from the eyepiece optical system 290.

  A half mirror 292 is disposed between the pentaprism 270 and the eyepiece optical system 290. The half mirror 292 superimposes the display image formed on the finder LCD 294 on the image on the focusing screen 272. Thereby, the image of the focusing screen 272 and the image of the finder LCD 294 can be seen together at the exit end of the eyepiece optical system 290. Note that information such as shooting conditions and setting conditions of the imaging apparatus 300 is displayed on the finder LCD 294.

  A part of the light emitted from the pentaprism 270 is guided to the photometry unit 280. The photometry unit 280 measures the intensity of incident light, its distribution, and the like, and refers to the measurement result when determining imaging conditions.

  On the other hand, a secondary mirror 242 is disposed on the back surface of the primary mirror 240 with respect to the incident light incident surface. The secondary mirror 242 guides part of the incident light transmitted through the primary mirror 240 to the focus detection device 230 disposed below. Thereby, when the primary mirror 240 is in the standby position, the focus detection device 230 detects the focus adjustment state of the optical system. When the primary mirror 240 is moved to the photographing position, the secondary mirror 242 is also retracted from the optical path of the incident light.

  A shutter 220, an optical filter 212, and an image sensor 210 are arranged along the optical axis behind the main mirror 240 with respect to the incident light from the lens barrel 100. When the shutter 220 is opened, the primary mirror 240 moves to the photographing position immediately before that, so that the incident light travels straight and enters the image sensor 210. As a result, the image formed by the incident light is converted into an electrical signal in the image sensor 210.

  In addition, the imaging unit 200 includes a main LCD 296 facing the outside on the rear surface with respect to the lens barrel 100. The main LCD 296 can display various setting information for the image capturing unit 200 and can display an image formed on the image sensor 210 when the primary mirror 240 is moved to the photographing position.

  The main control unit 250 comprehensively controls the various operations as described above. In addition, an autofocus mechanism that drives the lens barrel 100 can be formed by referring to information on the distance to the subject detected by the focus detection device 230 on the imaging unit 200 side. Furthermore, the focus detection device 230 can form a focus aid mechanism by referring to the operation amount of the lens barrel 100.

  Further, the main control unit 250 exchanges information with the microcomputer of the lens barrel 100 to control opening and closing of the diaphragm device 222 and the like. Further, the main control unit 250 contributes to automating exposure, execution of a scene mode, execution of bracket photography, and the like.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above-described embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

  The order of execution of each process such as operations, procedures, steps, and stages in the apparatus, system, program, and method shown in the claims, the description, and the drawings is particularly “before” or “prior to”. It should be noted that it can be realized in any order unless it is explicitly indicated as “,” etc., and the output of the previous process is not used in the subsequent process. Regarding the operational flow of the claims, the description, and the drawings, even if it is described using “first”, “next”, etc. for the sake of convenience, it means that it is essential to carry out in this order. is not.

It is sectional drawing in case the lens-barrel 100 exists in a wide angle end. It is sectional drawing in case the lens-barrel 100 exists in a telephoto end. It is sectional drawing in case the lens-barrel 101 exists in a wide angle end. It is sectional drawing in case the lens-barrel 101 exists in a telephoto end. 2 is a diagram schematically showing the structure of an imaging apparatus 300. FIG.

100, 101 Lens barrel, 110 Fixed barrel, 111 Engagement part, 185 Engagement part, 112 Base part, 113 Mount surface, 114 Guide part, 115 Motor chamber, 116, 181 Front side fitting part, 117 Rear side fitting part , 183 Rear fitting part, 118 support part, 119 support part, 120 focus ring, 122 transmission member, 124 tip part, 130 zoom ring, 132 guide groove, 140 middle cylinder, 142 cam follower, 145, 146, 161, 164 166 Cam groove, 152 Cam follower, 162 Cam follower, 172 Cam follower, 144 Inner cylinder, 176 Straight groove, 148 Engagement part, 149 Cam pin, 150 Outer cylinder, 155 Cover cylinder, 159 Lens frame, 189 Lens frame, 160 Cam cylinder, 174 Circumferential groove, 170 Interlocking cylinder, 180 Holding cylinder, 187 Pin, 192, 194 Guide bar, 200 Imaging unit, 210 Imaging device, 212 Optical filter, 220 Shutter, 222 Aperture device, 230 Focus detection device, 240 Primary mirror, 242 Sub mirror, 250 Main control unit, 260 Mount unit, 270 Penta prism, 272 focusing screen, 280 photometry unit, 290 eyepiece optical system, 292 half mirror, 294 finder LCD, 296 main LCD, 300 imaging device

Claims (5)

An axial guide shaft supported with respect to the reference member;
A holding member that holds the optical system and is movable with respect to the reference member in the axial direction of the guide shaft;
It has an engaging portion that engages with the holding member, and moves along the guide shaft without rotating the holding member by moving in the direction of the guide shaft while rotating around the optical axis of the optical system. An interlocking member that moves, and
The holding member has a groove provided along a circumferential direction around the optical axis of the optical system,
The interlocking member has a protrusion that engages with a groove of the holding member as the engaging portion,
The lens barrel according to claim 1, wherein the engaging portion engages at a position on an extension line of the guide shaft or a position between the extension line and a surface along the inner surface of the reference member . The lens barrel according to claim 1,
It has a cam groove which engages with the interlocking member, and has a drive cylinder which moves the interlocking member linearly in the direction of the guide shaft along the cam groove by rotating around the optical axis. Lens barrel. The lens barrel according to claim 1 or 2,
An operation member that is rotatably provided with respect to the reference member and that rotates the interlocking member by the rotation,
The lens barrel according to claim 1, wherein the groove has a length corresponding to a rotation angle of the operation member. In the lens barrel according to any one of claims 1 to 3,
The groove includes a cam portion inclined with respect to a surface orthogonal to the optical axis,
A lens barrel according to claim 1, wherein the engaging member moves relative to the cam portion to move the holding member in the direction of the guide shaft when the interlocking member rotates. The lens barrel according to any one of claims 1 to 4,
An imaging apparatus comprising: an imaging unit that captures an image by the optical system.

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