JP2006154173A - Lens device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive lens device with simple structure, which can be downsized and in which high reliability and durability are combined. <P>SOLUTION: The lens device has a zoom mechanism which changes focal length of a lens system, a focusing mechanism which adjusts an image forming position of the lens system, a driving source 1 which supplies driving force to the zoom mechanism and the focusing mechanism and allows reverse of the driving direction and a driving force transmission part T for transmitting the driving force to the zoom mechanism and the focusing mechanism. The driving force transmission part T is constituted to have a dead zone which transmits the driving force only to the focusing mechanism to block transmission of the driving force to the zoom mechanism during a fixed range after the driving direction of the driving source 1 is reversed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a lens device mounted on a camera, a portable electronic device, or the like, and more particularly to a lens device in which a zoom mechanism and a focus mechanism are operated by a single drive source.

  As a lens device including a zoom mechanism and a focus mechanism, for example, two drive sources are provided. When a zoom operation instruction is given, the zoom drive motor rotates, and the rotation is transmitted to the zoom cam ring. When the zoom operation is performed by moving back and forth, and the focus operation instruction is given, the focus drive motor rotates, the rotation is transmitted to the focus cam ring, and the focus lens group moves back and forth so that the focus operation is performed. What was made is well-known (for example, refer patent document 1).

  There has also been proposed a lens apparatus that includes a zoom / focus drive motor and performs a so-called step zoom operation. Such a lens device is configured as follows, for example. In other words, not only the zoom cam but also the focus cam is provided on the zoom cam ring. When a zoom operation instruction is given, the zoom / focus drive combined motor is rotated and the rotation is transmitted to the zoom cam ring. The zoom cam curve on the zoom cam ring is divided into two or more finite sections from the wide angle side to the telephoto side.

  When the cam follower moves from a certain section to an adjacent section, the zoom lens group moves back and forth with the rotation of the zoom cam ring to perform a zoom operation. On the other hand, paying attention to the area within one section, the focus lens group moves back and forth relative to the zoom lens group as the zoom cam ring rotates, so that the focus is moved back and forth as a whole lens system. During this time, the imaging magnification of the entire lens system is hardly changed, and the zoom operation is not expressed (see, for example, Patent Document 2).

  Further, the driving force from a single drive source is moved through the switching means, and the zoom lens moving means for moving the zoom lens group along the optical axis direction or the focus lens group in the optical axis direction. There has also been proposed a lens apparatus that can selectively transmit to a moving means for focusing that is moved along. For example, when the zoom lever that is rotatable between the neutral position and the tele position and the wide position on both sides thereof is operated to the tele position or the wide position by the operator, the gear train is zoomed. The gear train is configured to mesh with the drive mechanism side when in the neutral position or when a focus operation instruction is issued (see, for example, Patent Document 3).

Alternatively, it has a first transmission unit that transmits the output of the zoom / focus drive motor to the focus lens group, and a second transmission unit that also transmits the output to the zoom lens group. A lens device has also been proposed in which the transmission system is switched by the operation of a switching actuator using a piezoelectric element (see, for example, Patent Document 4).
JP 05-2123 A JP 09-329733 A JP 09-329736 A JP 05-249361 A

  The first conventional example (Patent Document 1) requires a total of two actuators (motors) for each of zoom and focus, which is disadvantageous in terms of cost and size. In the second conventional example (Patent Document 2), the focal length that can actually be used during zooming is a limited number of steps determined in advance by a section divided on the cam, and the lens system is particularly compact. In some cases, it is extremely difficult to form a large number of sections on the cam member due to dimensional restrictions, and as a result, the number of steps becomes extremely small, and there is a structural problem that the practicality is lowered.

  In the third conventional example (Patent Document 3), zoom and focus can be realized by a single actuator, but the mechanical structure becomes complicated and the number of parts increases, and the meshing of the gears can be switched. Since it occurs frequently, there is a concern that reliability and durability may be reduced due to mechanical wear.

  Furthermore, in the fourth conventional example (Patent Document 4), a switching actuator using a piezoelectric element is provided in addition to a zoom / focus drive combined motor, and as a result, two drive sources are used. As a result, the number of moving parts increases and the number of parts increases, making it difficult to simplify and compact the structure and reduce costs.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a lens apparatus capable of zooming and focusing with a single drive source, although the configuration is simple and compact.

(1) The lens device of the present invention includes a plurality of lens frames that hold at least two groups of lenses, and each lens frame is moved in a direction along the optical axis by a predetermined linkage operation, thereby focusing the lens system. A zoom mechanism for changing the distance, a focus mechanism for adjusting the imaging position of the lens system by moving at least one or all of the lens frames in a direction along the optical axis, and driving the zoom mechanism and the focus mechanism A driving source capable of supplying a force and capable of reversing the driving direction; and a driving force transmitting unit that transmits a driving force from the driving source to the zoom mechanism and the focusing mechanism, and the driving force transmitting unit includes: There is a dead zone that blocks transmission of driving force to either the zoom mechanism or the focus mechanism for a certain range after the drive direction of the drive source is reversed. And butterflies.

  According to such a configuration, for example, when the drive source is driven in the forward rotation direction, the zooming operation can be performed by transmitting the driving force to the zoom mechanism (and the focus mechanism). Next, after the zoom operation is completed, the drive source is reversed, so that due to the dead zone, the drive force is transmitted only to the focus mechanism without transmitting the drive force to the zoom mechanism within a predetermined range, and the focus operation is performed. be able to.

  As described above, the zoom operation and the focus operation can be performed by switching the drive direction of the (single) drive source between the forward and reverse directions by the drive force transmission unit having a simple configuration of the dead zone that does not transmit the drive force within a predetermined range. This can be performed selectively, and the number of parts of the apparatus is reduced, the configuration is simplified and the size can be reduced.

  In addition, since a dead zone is provided in the driving force transmission unit, a complicated configuration is unnecessary, and the configuration can be simplified, and movable parts can be reduced. Therefore, mechanical wear can be reduced, and reliability and durability can be improved.

As described above, according to the lens device of the present invention, it is possible to supply a lens device corresponding to zoom and focus with only one drive source, while having a small number of parts and a simple configuration and being inexpensive.
(2) The dead zone is formed by a transmission groove provided on the other in order to loosely engage a transmission pin provided on either the zoom mechanism or the focus mechanism, and the transmission pin is connected to the transmission groove. When it is in a position within the predetermined range that does not contact both terminals, the driving force may not be transmitted. For example, the dead zone can be formed in a range of 180 ° with a simple configuration in which the transmission groove is formed in a semicircular arc shape.
(3) The dead zone is formed by a contact portion provided at a predetermined interval on the other side in order to contact a transmission pin portion provided on either the zoom mechanism or the focus mechanism, When the transmission pin portion is in a position within the predetermined range where it does not contact the contact portion, the driving force may not be transmitted. In this way, the dead zone can be formed with a simpler configuration. For example, if the contact portion is disposed at a position facing the diametrical direction on the rotation trajectory of the transmission pin portion, it is 180 °. A dead zone can be formed in a range.

  The lens device of the present invention has a configuration in which a dead band that does not transmit driving force to either the zoom mechanism or the focusing mechanism within a predetermined range is provided, and a simple driving force transmission unit allows zooming with a single driving source. Since either one of the mechanism and the focus mechanism is selectively operated, a lens device having a small number of parts, a simple configuration, a low cost, and high reliability and durability can be supplied. .

Hereinafter, a lens device according to a best embodiment of the present invention will be described in detail with reference to the drawings.
[Embodiment 1]
FIGS. 1A and 1B are explanatory views of the configuration of a lens apparatus provided with a zoom mechanism and a focus mechanism, and FIG. 2 is a diagram corresponding to the assembly of a zoom cam ring and a fixed cylinder. As shown in these drawings, this lens device includes a single motor 1 as a drive source, and a pinion 2 attached to an output shaft thereof meshes with a focus cam ring 3 and an integrally fixed gear 3a.

  The main body of the focus cam ring 3 is formed in a columnar shape or a cylindrical shape, and a focus cam groove 4 forming a predetermined focus cam curve is formed on the outer peripheral surface thereof. A focus follower portion 5 is slidably fitted in the focus cam groove 4, and the base portion of the focus follower portion 5 projects into a zoom cam ring 7 that is movable along the direction of the optical axis 6 of the lens system. It is installed.

  The zoom cam ring 7 is formed in a cylindrical shape, and zoom cam grooves 7a and 7b forming a predetermined zoom cam curve are formed on the peripheral surface thereof. Zoom followers 8a and 9a are slidably fitted in the zoom cam grooves 7a and 7b, respectively. The zoom follower 8a protrudes from the first group lens frame 8, and the zoom follower 9a is a second group lens. It protrudes from the frame 9. Reference numerals 81 and 91 to 93 denote lenses.

  These two zoom follower portions 8a and 9a are also slidably fitted in translation grooves 10a and 10b formed in the fixed cylinder 10 in parallel with the optical axis 6, so that both lens frames 8 and 9 are slidably fitted. The movement direction is regulated in a direction parallel to the optical axis 6. The focus cam groove 4 and the focus follower portion 5 of the focus cam ring 3 constitute the main part of the focus mechanism of the present invention.

  On the other hand, a transmission ring 11 is arranged coaxially with the focus cam ring 3. That is, the shaft hole of the transmission ring 11 is rotatably fitted to the shaft 3 b protruding below the focus cam ring 3, and the gear portion 11 g formed on the outer periphery of the transmission ring 11 is connected to the zoom cam ring 7. It meshes with a gear portion 7g formed projecting on the outer periphery. A sensor 12 is disposed in the vicinity of the zoom cam ring 7. The sensor 12 is connected to the controller 13, and the controller 13 is connected to the power source 14 and the motor 1. The gear portion 11g of the transmission ring 11 and the gear portion 7g of the zoom cam ring 7 constitute the main part of the zoom mechanism of the present invention.

  A driving force transmission unit T for transmitting a driving force between the transmission ring 11 and the focus cam ring 3, that is, between the zoom mechanism and the focusing mechanism, is provided. It has a dead zone N that does not transmit driving force within a predetermined range. As shown in FIG. 1B, the driving force transmission portion T includes a transmission pin portion 16 fixed to the focus cam ring 3 and a semicircular transmission groove portion in which the transmission pin portion 16 is slidably fitted freely. The space of the transmission groove 15 forms a dead zone N (between the transmission pin 16).

  In the state shown in the drawing, when the transmission pin portion 16 rotates clockwise, the driving force is transmitted from the focus cam ring 3 to the transmission ring 11, but when the transmission pin portion 16 rotates counterclockwise, the transmission pin Since the portion 16 is separated from the pin position P of one end of the transmission groove portion 15, an angle θ (180 ° in this example) is reached until the transmission pin portion 16 reaches the pin position Q of the end of the other transmission groove portion 15. In the meantime, the driving force from the focus cam ring 3 is not transmitted to the transmission ring 11. That is, the driving force is not transmitted from the focus mechanism to the zoom mechanism.

  The operation of the lens apparatus configured as described above will be described. First, when the motor 1 rotates normally based on an instruction from the photographer or the like to perform the zoom operation, the focus cam ring 3 rotates via the pinion 2. To do. If the rotation direction is clockwise in FIG. 1B, the rotational force is transmitted from the transmission pin portion 16 at the pin position P contacting the one end of the transmission groove portion 15 to the transmission ring 11, and the focus cam ring. 3 and the transmission ring 11 also rotate clockwise.

  As a result, the zoom cam ring 7 is rotated via the gear portions 11g and 7g, and the zoom follower portions 8a and 9a of the lens frames 8 and 9 are restricted by the translation grooves 10a and 10b of the fixed barrel 10, and the zoom cam grooves 7a and 7b slide, and the lens frames 8 and 9 move in a direction along the optical axis 6 while maintaining a predetermined positional relationship with each other. The focal length of the lens system changes and zoom operation (magnification) is performed. Realize.

  Meanwhile, the rotation amount of the zoom cam ring 7 is detected by the sensor 12 and sent to the controller 13. The controller 13 monitors the detected rotation amount and controls and drives the motor 1. In addition to this position, the sensor 12 can be similarly controlled and driven by installing the sensor 12 in the vicinity of the transmission ring 11 and detecting the total amount of rotation of the transmission ring 14, for example.

  When the zoom operation is finished, the focal length has reached the user's desired zooming state, but the focus position is not guaranteed. Therefore, immediately after the end of the zoom operation, the focus operation is immediately performed. The focusing operation is performed by reversing the motor 1. That is, the reverse rotation of the motor 1 causes the focus cam ring 3 to rotate counterclockwise in FIG. Then, the transmission pin portion 16 integrated with the focus cam ring 3 does not transmit the rotational force to the transmission ring 11 while rotating by the angle θ from the initial pin position P to the pin position Q in the transmission groove portion 15.

  Since the transmission ring 11 does not rotate as described above within the range of the angle θ after the start of reverse rotation of the motor 1, the zoom cam ring 7 meshing with the transmission ring 11g and 7g does not rotate. Accordingly, the insertion positions of the zoom followers 8a and 9a of the lens frames 8 and 9 with respect to the zoom cam grooves 7a and 7b are also unchanged, and the focal length of the lens system does not change.

  On the other hand, the focus cam ring 3 also rotates within the range of the angle θ, and the insertion position of the focus cam groove 4 and the focus follower portion 5 of the zoom cam ring 7 changes. Therefore, according to the focus cam curve, The entire lens system held thereby translates along the optical axis 6. As a result, the focus position of the lens system moves with respect to the image pickup device 17 arranged in a fixed position. Therefore, when combined with an in-focus state detection means (not shown), the focus position can be adjusted on the surface (photoelectric conversion surface) of the image sensor 17 and a focusing operation is realized.

  According to this configuration, unlike the step zoom mechanism described above, the focus operation is independent of the zoom operation, so that it is possible to shift to the focus operation at any zoom position between the wide-angle end and the telephoto end. It is. In the above configuration, the focus cam curve drawn on the focus cam ring 3 is the point where the focus position is closest to the entire zoom range based on the latest shooting distance and the farthest shooting distance as the specifications of the zoom lens. The zoom cam ring 7 must be provided with an amount of translational movement that at least covers the range between and the most rearward point.

  The angle θ given as the predetermined value is about 180 degrees in FIG. 1B. However, the angle θ is not limited to this, and the angle θ is shorter or shorter as long as the formation length of the focus cam groove 4 in the circumferential direction can be covered. Also good. Actually, the formation length of the focus cam groove 4 in the circumferential direction is determined from the translational movement amount necessary for the focus operation and the inclination angle of the focus cam curve that is considered to be appropriate in design. Determined.

  Further, the focus operation is not limited to the reverse rotation with respect to the normal rotation during the zoom operation of the focus cam ring 3. If the focus position is excessively moved during the reverse rotation, the transmission pin portion 16 There is no problem even if the focus operation is continued by turning forward again within the range until the original pin position P is returned. In the above description, the focus cam ring 3 rotates clockwise during the zoom operation. However, the overall operation flow is the same even if this is reversed.

Here, in the present embodiment, the transmission ring 11 does not rotate within the range of the angle θ after the start of the reverse rotation of the motor. However, depending on the dimensional relationship of the parts when actually implemented, the friction of each part, etc. The possibility that the turning power is transmitted to the transmission ring 11 slightly due to the influence and the focal distance is shifted during the focusing operation cannot be denied. However, such troubles can be prevented, for example, by setting a sufficient clearance between the transmission pin portion 16 and the transmission groove portion 15 or providing a clutch mechanism in the transmission ring 11.
[Embodiment 2]
In the lens device according to the present embodiment, as shown in FIGS. 3A and 3B, the zoom cam ring 7 is disposed coaxially with the transmission ring 11 and the focus cam ring 3. In addition, the same code | symbol is attached | subjected about the same or equivalent member as previous embodiment.

  A focus cam surface 18 that draws a predetermined focus cam curve in the circumferential direction is formed on the lower end surface of the focus cam ring 3 in the figure. The focus follower portion 5 projecting inwardly on the inner side of the zoom cam ring 7 is in urging contact with the focus cam surface 18 so as to be slidable. The zoom cam ring 7 is rotatably fitted on the shaft portion 11b of the transmission ring 11 that is rotatably fitted on the shaft 3b of the focus cam ring 3, and is slidable in the axial direction. 19, the focus follower portion 5 is in slidable contact with the focus cam surface 18 in a constantly biased state. The focus cam surface 18 and the focus follower unit 5 constitute a main part of the focus mechanism of the present invention.

  Zoom cam surfaces 21a and 21b are formed on both upper and lower end surfaces of the zoom cam ring 7 so as to draw predetermined zoom cam curves 20a and 20b in the circumferential direction. An upper zoom cam surface 21 a in the drawing is provided for moving the first group lens frame 8, and a lower zoom cam surface 21 b is provided for moving the second group lens frame 9.

  Zoom followers 8a and 9a projectingly formed on both lens frames 8 and 9 are respectively in contact with the zoom cam surfaces 21a and 21b so as to be slidable in a constantly urged state by lens urging springs 22 and 23, respectively. ing. The shaft holes 8e and 9e formed in the lens frames 8 and 9, respectively, are slidably fitted on the guide shafts 24 and 25 disposed in a fixed state in the direction along the optical axis 6. The moving directions of both lens frames 8 and 9 are restricted only in the direction along the optical axis 6. The zoom cam surfaces 21a and 21b and the zoom follower portions 8a and 9a constitute the main part of the zoom mechanism of the present invention.

  On the other hand, a driving force transmission portion T is provided between the focus cam ring 3 and the transmission ring 11, and the driving force transmission portion T is a dead zone N that does not transmit a driving force within a predetermined range, as in the previous embodiment. have. That is, as shown in FIG. 3B, the driving force transmission portion T has a transmission pin portion 16 fixed to the focus cam ring 3 and a semicircular arc shape in which the transmission pin portion 16 is slidably fitted freely. The transmission groove 15 is formed, and the space of the transmission groove 15 forms a dead zone N (between the transmission pin 16).

  In the state shown in the drawing, when the transmission pin portion 16 rotates clockwise, the driving force is transmitted from the focus cam ring 3 to the transmission ring 11, but when the transmission pin portion 16 rotates counterclockwise, the transmission pin Since the portion 16 is separated from the pin position P of one end of the transmission groove portion 15, an angle θ (180 ° in this example) is reached until the transmission pin portion 16 reaches the pin position Q of the end of the other transmission groove portion 15. In the meantime, the driving force from the focus cam ring 3 is not transmitted to the transmission ring 11.

  A pair of convex portions 11 a and 11 a are formed on the outer circumference of the transmission ring 11 in the diametrical direction in the figure, and the convex portions 11 a and 11 a are formed on the inner peripheral surface of the zoom cam ring 7. It fits into the recessed portions 7a, 7a. In addition, at least one of the transmission ring 11 side or the zoom cam ring 7 side is formed long in the axial direction, and the recessed portion 7a and the convex portion 11a are fitted within the axial movement range of the zoom cam ring 7 with respect to the transmission ring 11. Is to be maintained. In this example, the recess 7a of the zoom cam ring 7 is formed long in the axial direction.

  The operation of the lens device configured as described above will be described. First, when the motor 1 rotates forward based on a zoom operation instruction from a photographer or the like, the focus cam ring 3 rotates via the pinion 2. If the rotation direction is clockwise in FIG. 3B, the rotational force is transmitted from the transmission pin portion 16 at the pin position P contacting the one end of the transmission groove portion 15 to the transmission ring 11, so that the focus cam ring 3 and the transmission ring 11 also rotate clockwise.

  Thereby, the rotation of the transmission ring 11 is transmitted to the zoom cam ring 7 through the fitting of the concave portion 7a and the convex portion 11a. When the zoom cam ring 7 rotates, the zoom followers 8a and 9a of the lens frames 8 and 9 slide on the zoom cam surfaces 21a and 21b, so that the lens frames 8 and 9 are in a predetermined relative positional relationship with each other. A zoom operation is realized in which the focal length of the lens system changes along the direction of the axis 6. Meanwhile, the rotation amount of the zoom cam ring 7 is detected by the sensor 12, and the detected value is sent to the controller 13. The controller 13 monitors the detected rotation amount and controls the motor 1.

  At the time when the zoom operation instruction is completed, the focal length has reached the user's desired zooming state, but the focus position is not guaranteed. Therefore, the focus operation is started immediately after the end of the zoom operation. The focusing operation is performed by reversing the motor 1. As a result of the reverse rotation, the focus cam ring 3 rotates counterclockwise in FIG. Then, the transmission pin portion 16 of the focus cam ring 3 only moves in the transmission groove portion 15 of the transmission ring 11 while rotating from the initial pin position P to the pin position Q by the angle θ, and rotates to the transmission ring 11. Power is not transmitted.

  Since the transmission ring 11 does not rotate as described above within the range of the angle θ after the start of the reverse rotation of the motor, the zoom cam ring 7 meshing with the transmission ring 11 does not rotate. Accordingly, the contact positions of the zoom followers 8a and 9a of the lens frames 8 and 9 with respect to the zoom cam surfaces 21a and 21b are also unchanged, and the focal length of the lens system does not change.

  On the other hand, the focus cam ring 3 also rotates within the range of the angle θ, and the contact position between the focus cam surface 18 and the focus follower portion 5 of the zoom cam ring 3 changes. Therefore, the zoom cam ring 7 and the entire lens system held in contact with the zoom cam ring 7 translate in the direction of the optical axis 6 according to the focus cam curve. That is, the focus position of the lens system moves with respect to the image sensor 17 whose position does not change. Accordingly, when combined with an in-focus state detection means (not shown), the focus position can be adjusted on the surface (photoelectric conversion surface) of the image sensor 17 and a focusing operation can be performed.

As in the previous embodiment, according to this configuration, unlike the step zoom mechanism described above, the focus operation is independent of the zoom operation, so the focus operation is shifted to any zoom position between the wide-angle end and the telephoto end. Is possible. Note that the conditions imposed on the focus cam curve, the angle θ, and supplements regarding forward and reverse rotation during the focus operation are the same as in the previous embodiment.
[Embodiment 3]
In the lens device according to the present embodiment, as shown in FIGS. 4A and 4B, the zoom cam ring 7 is disposed coaxially with the focus cam ring 3, and the transmission ring according to the previous embodiment is provided. 11 is omitted, and the driving force transmission function is exhibited by the zoom cam ring 7. In addition, the same code | symbol is attached | subjected about the same or equivalent member as previous embodiment.

  On the end surface of the focus cam ring 3 that is rotated by the motor 1, a focus cam surface 18 that draws a predetermined focus cam curve in the circumferential direction is formed. A zoom cam ring 7 is disposed so that the focus follower unit 5 is brought into contact with the focus cam surface 18. That is, the zoom cam ring 7 is rotatably and slidably fitted on the shaft 3 b of the focus cam ring 3, and the zoom follower spring 19 keeps the focus follower unit 5 always biased with respect to the focus cam surface 18. It is in contact with sliding freely. The focus cam surface 18 and the focus follower unit 5 constitute a main part of the focus mechanism of the present invention.

  Zoom cam surfaces 21a and 21b are formed on both upper and lower end surfaces of the zoom cam ring 7 so as to draw predetermined zoom cam curves 20a and 20b in the circumferential direction. An upper zoom cam surface 21 a in the drawing is provided for moving the first group lens frame 8, and a lower zoom cam surface 21 b is provided for moving the second group lens frame 9.

  Zoom followers 8a and 9a projectingly formed on both lens frames 8 and 9 are slidably contacted with the zoom cam surfaces 21a and 21b in a constantly urged state by lens urging springs 22 and 23, respectively. Abut. The shaft holes 8e and 9e formed in the lens frames 8 and 9, respectively, are slidably fitted on the guide shafts 24 and 25 disposed in a fixed state in the direction along the optical axis 6. The moving directions of both lens frames 8 and 9 are restricted only in the direction along the optical axis 6. The zoom cam surfaces 21a and 21b and the zoom follower portions 8a and 9a constitute the main part of the zoom mechanism of the present invention.

  The zoom cam ring 7 is provided with contact portions 7p and 7q corresponding to the rotation trajectory of the transmission pin portion 16 provided on the focus cam ring 3, and the transmission pin portion 16 and the contact portions 7p and 7q. Thus, a driving force transmission portion T is configured, and this driving force transmission portion T has a dead zone N that does not transmit a driving force within a predetermined range, as in the previous embodiments. That is, as shown in FIG. 4B, the driving force transmission portion T is configured by a transmission pin portion 16 fixed to the focus cam ring 3 and contact portions 7p and 7q that abut the transmission pin portion 16. The space between the contact portions 7p and 7q forms a dead zone N (between the transmission pin portion 16).

  The operation of the lens apparatus configured as described above will be described. First, when the motor 1 rotates normally based on a zoom operation instruction from a photographer or the like, the focus cam ring 3 rotates via the pinion 2. If the rotation direction is clockwise in FIG. 4B, the rotational force is transmitted from the transmission pin portion 16 at the pin position P that contacts one of the contact portions 7p to the contact portion 7p. The zoom cam ring 7 rotates in the clockwise direction together with the cam ring 3.

  When the zoom cam ring 7 rotates, the zoom followers 8a and 9a of the lens frames 8 and 9 slide on the zoom cam surfaces 21a and 21b, and the lens frames 8 and 9 are in a predetermined positional relationship with each other and the optical axis 6 A zoom operation in which the focal length of the lens system changes is realized. Meanwhile, the rotation amount of the zoom cam ring 7 is detected by the sensor 12, and the detected value is sent to the controller 13. The controller 13 monitors the detected rotation amount and controls the motor 1.

  At the time when the zoom operation instruction is completed, the focal length has reached the user's desired zooming state, but the focus position is not guaranteed. Therefore, the focus operation is started immediately after the end of the zoom operation. The focusing operation is performed by reversing the motor 1. As a result of the reverse rotation, the focus cam ring 3 rotates counterclockwise in FIG. Then, the transmission pin portion 16 of the focus cam ring 3 only moves in the space between the contact portions 7p and 7q while rotating from the initial pin position P to the pin position Q by the angle θ, and the zoom cam ring 7 No rotational power is transmitted.

  Since the zoom cam ring 7 does not rotate as described above within the range of the angle θ after the start of the reverse rotation of the motor, the contact positions of the zoom followers 8a and 9a of the lens frames 8 and 9 with respect to the zoom cam surfaces 21a and 21b remain unchanged. However, the focal length of the lens system does not change.

  On the other hand, the focus cam ring 3 also rotates within the range of the angle θ, and the contact position between the focus cam surface 18 and the focus follower portion 5 of the zoom cam ring 7 changes. Therefore, the zoom cam ring 7 and the entire lens system held in contact with the zoom cam ring 7 translate in the direction of the optical axis 6 according to the focus cam curve. That is, the focus position of the lens system moves with respect to the image sensor 17 whose position does not change. Accordingly, when combined with an in-focus state detection means (not shown), the focus position can be adjusted on the surface (photoelectric conversion surface) of the image sensor 17 and a focusing operation can be performed.

As in the previous embodiments, according to this configuration, unlike the step zoom mechanism described above, the focus operation is independent of the zoom operation, so the focus operation can be performed at any zoom position between the wide-angle end and the telephoto end. It is possible to migrate. Note that the conditions imposed on the focus cam curve, the angle θ, and supplements regarding forward and reverse rotation during the focus operation are the same as in the previous embodiments.
[Embodiment 4]
The lens device according to the present embodiment is shown in FIGS. 5 (a) and 5 (b) and FIGS. 6 (a) and 6 (b). In each of the embodiments described above, the entire lens system is moved during the focusing operation, whereas in this embodiment, the focusing operation is performed by moving a part of the lens group constituting the lens system. Do. Specifically, the focusing operation is performed by moving only the third group lens frame 26 among the three groups of lens frames 81, 9 and 26. In addition, the same code | symbol is attached | subjected about the same or equivalent member as previous embodiment.

  An upper cam ring 31 is rotatably fitted on an upper shaft portion 3c that forms a support shaft of a gear 3a that meshes with a pinion (gear) 2 attached to the output shaft of the motor 1, and is integrated with the upper shaft portion 3c. The lower cam portion 3e protruding from the intermediate shaft portion 3d is rotatably fitted with the lower cam ring 32 so that the cam rings 31, 32 are relatively movable in the axial direction. Is partially fitted to the lower cam ring 32 in a coaxial manner.

  More specifically, the opposing end surfaces of the fitting portions of both cam rings 31 and 32 are formed in an inclined shape, and a plurality of vertical grooves that mesh with each other are formed in the fitting surface in the axial direction. The cam rings 31 and 32 are constrained and rotated together in the circumferential direction, and are slidable in the axial direction.

  The upper cam ring 31 is formed with a zoom cam surface 21a that draws a predetermined zoom cam curve 20a in the circumferential direction. The zoom cam surface 21a is mainly changed (zoomed) in focal length by a lens biasing spring 22. The zoom follower portion 9a of the second group lens frame 9 is always in contact with the energized state.

  The lower cam ring 32 is formed with a zoom cam surface 21b that draws a predetermined zoom cam curve 20b in the circumferential direction. The zoom cam surface 21b is mainly subjected to a change in focus, that is, a focus position by a lens biasing spring 23. The zoom follower portion 26a of the third group lens frame 26 is always in contact with the biased state. The zoom cam surface 21a and the zoom follower portion 9a of the upper cam ring 31 and the zoom cam surface 21b and the zoom follower portion 26a of the lower cam ring 32 constitute the main part of the zoom mechanism of the present invention.

  A lens 81 held in a first group lens frame (not shown) is held in a fixed position in the apparatus. In addition, the second group lens frame 9 and the third group lens frame 26 have their shaft holes 9e and 26e slidable on guide shafts 24 and 25 arranged in a fixed state in the direction along the optical axis 6, respectively. The movement direction of both lens frames 9 and 26 is restricted only in the direction along the optical axis 6. Reference numeral 261 denotes a lens held by the third group lens frame 26.

  A transmission pin portion 16 protrudes downward from the intermediate shaft portion 3d described above, and a transmission groove portion 15 for loosely fitting the transmission pin portion 16 is formed in the lower cam ring 32. The tip of the transmission pin portion 16 is in contact with a focus cam surface 21c that draws a predetermined focus cam curve 20c in the circumferential direction provided on the inner surface of the lower cam ring 32 (the focus cam surface 21c is the transmission pin portion 16). Is in slidable contact with the tip of the urging state). The focus cam surface 21c and the transmission pin portion 16 constitute the main part of the focus mechanism of the present invention. A sensor 12 is disposed in the vicinity of the lower cam ring 32 and is connected to the controller 13, to which the power supply 14 and the motor 1 are connected.

  A driving force transmission portion T for transmitting a driving force between the zoom mechanism and the focus mechanism is provided between the transmission pin portion 16 and the lower cam ring 32. The driving force transmission portion T has a predetermined range. It has a dead zone N that does not transmit driving force. That is, as shown in FIGS. 5 (b) and 6 (b), the driving force transmission portion T is configured to contact the transmission pin portion 16 provided on the intermediate shaft portion 3d with the transmission pin portion 16. A semicircular groove-like space between the contact portions 32p and 32q forms a dead zone N (between the transmission pin portion 16).

  The operation of the lens apparatus configured as described above will be described. First, when the motor 1 rotates forward based on a zoom operation instruction from a photographer or the like, the intermediate shaft portion 3d rotates via the pinion 2. If the direction of rotation is clockwise in FIG. 5B, the rotational force is transmitted from the transmission pin portion 16 at the pin position P that contacts one of the contact portions 32p to the contact portion 32p. Along with the cam ring 32, the upper cam ring 31 also rotates clockwise.

  When the upper cam ring 31 and the lower cam ring 32 rotate, the lens frames 9 and 26 move in a direction along the optical axis 6 while maintaining a predetermined positional relationship with each other, and a zoom operation in which the focal length of the lens system changes is performed. Realized. In the meantime, the rotation amount of the lower cam ring 32 is detected by the sensor 12, and the detected value is sent to the controller 13, which monitors the detected rotation amount and drives and controls the motor 1.

  At the time when the zoom operation instruction is completed, the focal length has reached the user's desired zooming state, but the focus position is not guaranteed. Therefore, the focus operation is started immediately after the end of the zoom operation. The focusing operation is performed by reversing the motor 1. As a result of the reverse rotation, the intermediate shaft portion 3d rotates counterclockwise in FIG. Then, the transmission pin portion 16 of the intermediate shaft portion 3d only moves in the space (dead zone) between the contact portions 32P and 32Q while rotating by the angle θ from the initial pin position P to the pin position Q. The turning force is not transmitted to the cam ring 32.

  Since the lower cam ring 32 and the upper cam ring 31 do not rotate within the range of the angle θ after the reverse rotation of the motor 1 as described above, the zoom follower portion of the lens frames 9 and 26 with respect to the zoom cam surfaces 21a and 21b. The contact positions of 9a and 26a are also unchanged, and the focal length of the lens system does not change.

  On the other hand, the intermediate shaft portion 3d rotates even within the range of the angle θ, and the contact position between the transmission pin portion 16 and the focus cam surface 20c changes. Therefore, as shown in FIG. 6A, the lower cam ring 32 is pushed downward, and only the third lens group frame 26 moves downward in the axial direction. As a result, the focus position of the lens system moves with respect to the image sensor 17 whose position does not change. Therefore, when combined with an in-focus state detection unit (not shown), the focus position can be adjusted to the surface (photoelectric conversion surface) of the image sensor 17 and a focusing operation is realized.

  As in the previous embodiments, according to this configuration, unlike the step zoom mechanism described above, the focus operation is independent of the zoom operation, so the focus operation is performed at any zoom position between the wide-angle end and the telephoto end. It is possible to migrate to. Note that the conditions imposed on the focus cam curve, the angle θ, and supplements regarding forward and reverse rotation during the focusing operation are the same as those in the first embodiment. In this embodiment, as an example, focusing is performed by moving the third group lens frame 26 out of the three lens frame groups constituting the lens group. You may make it move.

  It should be noted that the present invention is not limited to the configuration of each of the above-described embodiments, and can be freely changed in design or improved as necessary without departing from the gist of the invention. The dead zone provided in the unit may be configured so as not to transmit the driving force within a predetermined range when the driving direction of the driving source is changed, and is not limited in its configuration or type.

  The lens device according to the present invention selectively selects either the zoom mechanism or the focus mechanism with a single drive source by a drive force transmission unit that has a simple configuration of a dead zone that does not transmit a drive force within a predetermined range. Therefore, the present invention can be applied to the field of compact cameras and the like that are required to be compact and inexpensive.

  The lens device according to the present invention selectively selects either the zoom mechanism or the focus mechanism with a single drive source by a drive force transmission unit that has a simple configuration of a dead zone that does not transmit a drive force within a predetermined range. Therefore, for example, it is useful for providing high reliability and durability in the field of a small camera or the like.

(A) is structure explanatory drawing of the lens apparatus which concerns on Embodiment 1 of this invention, (b) is AA arrow sectional drawing of (a). Assembly view of the zoom cam ring and fixed cylinder (A) is structure explanatory drawing of the lens apparatus which concerns on Embodiment 2 of this invention, (b) is the sectional view on the AA line of (a). (A) is structure explanatory drawing of the lens apparatus which concerns on Embodiment 3 of this invention, (b) is the sectional view on the AA line of (a). (A) is structure explanatory drawing of the lens apparatus which concerns on Embodiment 4 of this invention, (b) is the sectional view on the AA line of (a). (A) is structure explanatory drawing when the state of the lens apparatus based on Embodiment 4 of this invention changes, (b) is an AA arrow directional cross-sectional view of (a).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Drive source 6 Optical axis 7 Zoom cam ring 8, 9, 26 Lens frame 15 Transmission groove part 16 Transmission pin part 7p, 7q, 32p, 32q Contact part T Driving force transmission part N Dead zone

Claims (3)

A plurality of lens frames that hold at least two groups of lenses; a zoom mechanism that changes the focal length of the lens system by moving each of the lens frames in a direction along the optical axis by a predetermined linkage operation; and the lens A focus mechanism that adjusts the imaging position of the lens system by moving at least one or all of the frames in a direction along the optical axis, and a driving force can be supplied to the zoom mechanism and the focus mechanism to reverse the driving direction. And a driving force transmission unit that transmits a driving force from the driving source to the zoom mechanism and the focus mechanism.
The drive force transmission unit has a dead zone that blocks transmission of drive force to either the zoom mechanism or the focus mechanism for a certain range after the drive direction of the drive source is reversed. Lens device.   The dead zone is formed by a transmission groove portion provided on the other side for loosely fitting a transmission pin portion provided on either the zoom mechanism or the focus mechanism, and the transmission pin portion is provided at both ends of the transmission groove portion. The lens apparatus according to claim 1, wherein the driving force is not transmitted when the lens is in a position within the predetermined range where it does not contact.   The dead zone is formed by a contact portion provided at a predetermined interval on the other side in order to contact a transmission pin portion provided on either the zoom mechanism or the focus mechanism, and the transmission pin portion 2. The lens device according to claim 1, wherein the driving force is not transmitted when the lens is in a position within the predetermined range that does not contact the contact portion.

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