JP2010072536A - Imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging apparatus enabling construction of a small bending optical system with high magnification. <P>SOLUTION: The imaging apparatus includes at least two object-side lens groups (25 and 26) located on an object side. Further, the imaging apparatus includes a prism 9 which is located on a first optical axis (optical axis A) being the optical axis of the object-side lens groups, bends the first optical axis to guide it to a second optical axis (optical axis B) and is retracted along the second optical axis in a non-shooting state. The second lens group 26 located on the side of the prism 9, of the object-side lens groups includes a second group holding member 40 drive-controlled along the first optical axis and a second group lens holder 7 holding the second lens group 26. The second group lens holder 7 includes a flange part 7a pressed and retracted by the first lens group 25 in the non-shooting state. In the non-shooting state, at least, the second lens group 26 is retracted and accommodated in a space defined by the second group holding member 40 and the rear part of the second group lens holder 7 and a space occupied by the prism 9 in a shooting state. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an imaging apparatus including an optical element driving mechanism that drives an optical element using a bending optical system.

  Conventionally, there is a technique disclosed in Patent Document 1 regarding this type of imaging apparatus.

  That is, the camera (imaging device) disclosed in Patent Document 1 uses a one-side cam ring opened in front of the optical axis, and springs the second and third lens groups against the cam surface along the optical axis direction. The lens group is driven and controlled in accordance with the zooming operation.

In addition, when the camera is retracted, the first group lens is retracted in a state where a part of the second and third group lenses and the camera body are in contact with each other. Thinning is realized by releasing the contact and storing.
Japanese Patent Laid-Open No. 11-271829

  In the above prior art, the optical system is a three-group imaging optical system in which the first group lens, the second group lens are driven by a cam mechanism, and the third group lens is driven and controlled by another driving source such as a stepping motor. . When the lens barrel is retracted, the second group lens holding the third group lens comes into contact with the main body, and further, the first group lens is retracted to the storage position, so that the spring force is exerted between the first group lens and the second group lens. By making it narrower, it is thinner.

  However, there is no disclosure of an optical system using a reflective optical element or a mechanism for retracting the reflective optical element when stored. In other words, the above-described prior art can only be applied to a zoom optical system having a small variable magnification, and cannot be applied to an optical system using a reflective optical element corresponding to a high magnification.

  An object of the present invention is to provide an imaging apparatus capable of constructing a compact and high-magnification bending optical system.

  In order to achieve the above object, an imaging apparatus according to claim 1 is located on at least two object side lens groups located on the object side and a first optical axis that is an optical axis of the object side lens group. A reflective optical element that bends the first optical axis and guides it to the second optical axis, and retracts along the second optical axis in a non-photographing state, of the object side lens group The second lens group positioned on the reflective optical element side includes a drive frame that is driven and controlled along the first optical axis, and a lens holding frame that holds the second lens group, and the lens The holding frame has a contact portion that is pressed and retracted by a first lens group located on the object side of the object side lens group in the non-photographing state, and in the non-photographing state, A space formed with a rear portion of the lens holding frame; and In the space located in the reflective optical element at the time of shadow, characterized in that at least the second lens group is accommodated retracted.

  According to the imaging apparatus of the present invention, a compact and high-magnification bending optical system can be constructed.

  Hereinafter, the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a main part configuration diagram showing a WIDE state in which the photographing lens system (lens barrel) in the imaging apparatus according to the embodiment of the present invention has a wide angle.

  The G1 lens 1 is held by the first group lens holder 3 to form a first lens group 25.

  The G4 lens 5 is incorporated in the second group lens holder 7 and constitutes the second lens group 26.

  The first lens group 25 and the second lens group 26 constitute at least two object side lens groups located on the object side.

  The second group lens holder 7 is connected and fixed to the second group holding member 40 by the action (elastic force) of a spring 41.

  The lens is driven back and forth by a driving source such as a stepping motor along the direction of the optical axis A in the drawing to perform a zooming operation. At this time, a space C in the figure exists between the rear portion of the second group lens holder 7 and the second group holding member 40.

  The prism 9 is a reflective optical element that acts to bend the optical axis (photographing optical axis) A from the subject by 90 °, and the optical axis A (first optical axis) is directed to the optical axis B that forms approximately 90 °. It is guided. The prism 9 is held by the prism holding member 10 so that it can advance and retreat along the optical axis B.

  More specifically, the prism 9 is positioned on the first optical axis that is the optical axis of the object-side lens group, bends the first optical axis, guides it to a second optical axis to be described later, and is in a non-photographing state. The reflecting optical element is retracted along the second optical axis.

  The G7 lens 11 advances and retreats along the optical axis B (second optical axis), and is fixed to the shutter front base plate 13. At the rear part, a shutter and iris mechanism 15 that controls the amount of photographing light with the rear shutter base plate 14 is disposed.

  After that, the G9 lens 16 is held by a holding member, and is supported so as to be movable integrally with the rear shutter base plate 14 in the optical axis B direction. In this state, the third lens group 18 of the photographing lens is configured, and the third lens group 18 performs a zooming operation by appropriately moving back and forth along the optical axis B.

  The G11 lens 19 constitutes the fourth lens group 22 and is held by the fourth group lens holder 21.

  The fourth lens group 22 is configured by the above components, and the fourth lens group 22 is appropriately advanced and retracted by a drive source such as a stepping motor along the optical axis B, so that zooming and focusing operations are performed. .

  An optical filter 23 having a low-pass filter function for cutting light with a high spatial frequency and a function for cutting infrared light is disposed on the front surface of the image sensor 24.

  Thus, the photographing optical system is completed, and the subject image is formed on the image sensor 24, whereby the photographed image is converted into an electrical signal and an electrophotographic image is obtained.

  Here, the drive source for driving the first lens group 25 and the drive source for driving the reflective optical element (prism 9) are the same, and the first lens group 25 is along the first optical axis (optical axis A). There is a region where the reflective optical element is not driven.

  FIG. 2 is a main part configuration diagram showing a TELE state in which the photographing lens system in the imaging apparatus according to the embodiment of the present invention has a long focal point.

  1, the first lens group 25 is fixed in that position, and the second lens group 26 is driven back along the optical axis A by a stepping motor or the like not shown. Located in the direction of approaching.

  The third lens group 18 is driven along the optical axis B by a stepping motor or the like (not shown), and is positioned in the direction approaching the prism 9 like the second lens group 26. The fourth lens group 22 is also driven in the direction of the optical axis B by a stepping motor or the like (not shown), and stops in a state of approaching the image sensor 24.

  FIG. 3 is a main part configuration diagram showing a storage state of the photographing lens system in the imaging apparatus of FIGS. 1 and 2.

  As will be described later, the prism 9 is driven to a position retracted from the optical axis A along the optical axis B. Accordingly, the second lens group 26 and the first lens group 25 are accommodated along the optical axis A. It is driven up to.

  When the prism 9 is retracted, it is retracted to a position where the third lens group 18 and the fourth lens group 22 do not interfere with each other to form a retracted state. At this time, it can be seen that the second lens group 26 is retracted to a position overlapping a part of the space where the prism 9 was located at the time of photographing.

  Further, when forming this storage state, the second group contact portion 34a of the first group lens barrel 34 contacts the flange portion 7a of the second group lens holder 7, and the second group lens holder 7 is moved against the urging force of the spring 41. Retract to the storage position. Accordingly, it can be seen that the second lens group 26 is housed in the space C formed between the rear portion of the second group lens holder 7 and the second group holding member 40.

  Therefore, the maximum storage effect can be obtained by retracting the second lens group 26 with respect to the space and the space C where the prism 9 is located.

  Of the object side lens group, the second lens group 26 located on the reflective optical element side includes a drive frame (second group holding member 40) that is driven and controlled along the first optical axis, and a second lens group 26. It is comprised with the lens holding frame (2 group lens holder 7) to hold | maintain.

  The lens holding frame has a contact portion (flange portion 7a) that is pressed and retracted by the first lens group 25 located on the object side in the object side lens group in the non-photographing state. In the non-photographing state, at least the second lens group 26 is retracted and retracted in a space formed by the drive frame and the rear portion of the lens holding frame and a space where the reflective optical element is located at the time of photographing.

  Next, the drive mechanism and prism retracting mechanism of the first lens group 25 will be described with reference to FIG.

  FIG. 4 is a perspective view of a main part showing a housed state of the taking lens system in the image pickup apparatus of FIGS. 1 and 2.

  A pinion gear 28 is press-fitted into the output shaft of the motor 27, and a reduction gear train 29 is gear-coupled thereto. A driving gear 30 extending in the direction of the optical axis A is attached to the fixed cylinder 31 at the final stage of the reduction gear train 29.

  A cam groove 31a (FIG. 6), which will be described later, is formed on the inner surface of the fixed cylinder 31, and a cam pin 32a fixed to or integrated with the differential cylinder 32 is slidably engaged with the cam groove 31a. Match. The differential cylinder 32 is formed with a gear (not shown) that is screwed with the drive gear 30, and the differential cylinder 32 is rotationally driven in response to the output of the drive gear 30.

  At this time, the differential cylinder 32 moves forward and backward along the optical axis A by the action of the cam groove 31a. In the inner diameter portion of the differential cylinder 32, a rectilinear guide cylinder 33 is disposed so as to be rotatable relative to the differential cylinder 32 and to advance and retract integrally in the optical axis A direction.

  Further, a cam groove 32 b (FIGS. 1 and 3) is formed in the inner diameter portion of the differential cylinder 32. Between the inner diameter part of the differential cylinder 32 and the outer diameter part of the linear guide cylinder 33, a first group barrel 34 (FIG. 1) holding the first lens group 25 is held.

  A cam pin 35 (FIG. 1) fixed to or integrally molded with the first group barrel 34 and the cam groove 32b are slidably engaged. Further, in the straight guide tube 33, a convex portion in the optical axis A direction (not shown) provided on the outer peripheral portion is slidably engaged with an engagement groove formed in the inner peripheral portion of the first group barrel 34. Thus, the movement of the first group barrel 34 in the rotational direction is restricted.

  When the differential cylinder 32 starts rotating upon receiving the driving force of the motor 27, the cam groove 32b formed on the inner peripheral surface of the differential cylinder 32 and the cam pin 35 of the first group lens barrel 34 are engaged and go straight. The engaging action of the convex part provided in the guide cylinder 33 and the engaging groove formed in the inner peripheral part of the first group barrel 34 works. Due to these engaging actions, the first group lens barrel 34 advances and retreats along the optical axis with respect to the differential cylinder 32.

  Therefore, when the differential cylinder 32 advances and retreats along the optical axis A with respect to the fixed cylinder 31, the first group barrel 34 further advances and retreats with respect to the differential cylinder 32, and the first lens group 25 is moved from the storage position. It is configured to drive to the shooting position.

  The prism holding member 10 is formed with engaging portions 10a and 10b which hold the prism 9 therein and engage with the two guide shafts 36 and 37 so as to be slidable in the optical axis B direction.

  The engaging portion 10a is formed with a protrusion 10c that engages with the driving groove 38a of the prism driving lever 38, and advances and retracts the prism 9 along the optical axis B as will be described later. The prism drive lever 38 has a rotation center 38b slidably supported by a camera (imaging device) main body (not shown).

  A prism drive gear 39 is gear-coupled further ahead of the reduction gear train 29 and the drive gear 30. While receiving the driving force of the motor 27, the prism drive gear 39 rotates in the clockwise direction in FIG. 4 while the first group barrel 34 is extended to the photographing standby position along the optical axis A, but the engaging portion 39a is Continue idling.

  Then, after the first lens barrel 34 is set at the photographing position, the engaging portion 39a engages with the driven portion 38c of the prism driving lever 38, and the prism driving lever 38 is rotated counterclockwise around the rotation center 38b. Rotating drive.

  With this rotational force, the driving groove 38a of the prism driving lever 38 drives the projection 10c of the prism holding member 10 along the optical axis B, and the prism 9 is set to the photographing position.

  Thus far, the lens barrel optical system is ready for shooting.

  FIG. 5 is a perspective view of a main part showing a state in which the first lens group 25 and the prism 9 in FIG. 1 are set in a photographing state.

  At this time, the second lens group 26 is set at the photographing standby position by a known support and driving means. As described above, the motor 27 continues to rotate even after the first group barrel 34 is extended to the imaging standby position and the second lens group 26 is extended to the imaging standby position.

  The engaging portion 39a of the prism driving gear 39 engages with the driven portion 38c of the prism driving lever 38 and rotates it, and the driving is stopped in a state where the prism 9 is set at the photographing standby position shown in FIG.

  FIG. 6 is a diagram in which the cutout portion 31b through which the prism 9 of the fixed cylinder 31 in FIG.

  A plurality of cam grooves 31a are slidably engaged with cam pins 32a fixedly or integrally attached to the differential cylinder 32.

  The cam pin 32a shown in FIG. 6 represents a state where the differential cylinder 32 is in the storage position. When the motor 27 starts to rotate, the cam pin 32a is driven in the right direction in FIG. 6 and extends the first lens group 25 in the direction of the optical axis A in the section of the cam groove 31a-1.

  When the cam pin 32a enters the cam groove 31a-2, the differential cylinder 32 continues to rotate, but the first lens group 25 remains in that position. When the cam pin 32a enters the cam groove 31a-2, the engaging portion 39a of the prism drive gear 39 drives the prism drive lever 38 to set the prism 9 at the photographing position.

  The movement from the photographing state to the retracted state is the reverse of the above-described movement, and after the prism 9 is retracted from the fixed cylinder 31, the first lens group 25 and the second lens group 26 are accommodated in the camera body.

  FIG. 7 is a cross-sectional perspective view of a main part showing a photographing state (WIDE) of the first lens group 25 and the second lens group 26 in FIG.

  In this state, the optical axis position of the second group lens holder 7 is determined by the positioning contact portion 40a of the second group holding member 40 by the spring 41 as described above and integrated with the second group holding member 40. It can move in the direction.

  At this time, in the event of an impact from the outside or a fall accident, the second group lens holder 7 opposes the spring force and is disconnected from the second group holding member 40, for example, collides with the prism holding member 10 and breaks them. In order to prevent this, the following locking mechanism is provided.

  FIG. 8 is a cross-sectional view of a principal part showing a lock mechanism in the imaging apparatus of FIGS. 1 and 2.

  In the photographing state of FIG. 8A, when a drop impact force is applied to the second group lens holder 7 in the downward direction in the figure, it interferes with a lock lever (regulating member) 42 provided on the second group holding member 40. Can not move more than a certain amount. Therefore, breakage of these parts can be avoided.

  When shifting from the photographing state to the non-photographing state, the restriction of the lock lever (regulating member) 42 is released by the holding member (first group barrel 34) that holds the first lens group 25.

  However, in this state, the second group lens holder 7 cannot be retracted with respect to the second group holding member 40 during the storing operation. Therefore, the unlocking mechanism operates as described below to enable the storing operation.

  When the storing operation is started and the prism 9 is retracted along the optical axis B to the outside of the lens barrel, when the first group lens barrel 34 begins to retract along the optical axis A, the first group lens barrel 34 is first unlocked. The part 34b rotates the lock lever 42 counterclockwise against a spring force (not shown).

  In the figure, when the lock lever 42 rotates about 90 °, the lock lever 42 and the second group lens holder 7 do not interfere with each other in the optical axis direction.

  8B, the second group contact portion 34a of the first group lens barrel 34 contacts the flange portion 7a of the second group lens holder 7, and the second group lens holder against the urging force of the spring 41. 7 can be retracted to the storage position.

  FIG. 9 is a cross-sectional perspective view of a main part showing a storage state of the first lens group 25 and the second lens group 26 in FIG.

  As described above, by realizing the lock mechanism and the release mechanism of the second group lens holder 7, it is possible to achieve both downsizing and impact resistance.

  Although the embodiment of the present invention has been described in detail above, the present invention is not limited to this embodiment.

It is a principal part block diagram which shows the WIDE state in which the imaging lens system (lens barrel) in the imaging device which concerns on embodiment of this invention is a wide angle. It is a principal part block diagram which shows the TELE state in which the imaging lens system in the imaging device which concerns on embodiment of this invention has a long focus. It is a principal part block diagram which shows the accommodation state of the imaging lens system in the imaging device of FIG. 1, FIG. It is a principal part perspective view which shows the accommodation state of the imaging lens system in the imaging device of FIG. 1, FIG. It is a principal part perspective view which shows the state in which the 1st lens group 25 and the prism 9 in FIG. 1 were set to the imaging state. FIG. 5 is a diagram in which a cutout portion 31b through which the prism 9 of the fixed cylinder 31 in FIG. FIG. 2 is a cross-sectional perspective view of a main part showing a photographing state (WIDE) of a first lens group 25 and a second lens group 26 in FIG. 1. It is principal part sectional drawing which shows the locking mechanism in the imaging device of FIG. 1, FIG. FIG. 2 is a cross-sectional perspective view of a main part showing a storage state of a first lens group 25 and a second lens group 26 in FIG. 1.

Explanation of symbols

7 Second lens group holder 7a Flange portion 9 Prism 25 First lens group 26 Second lens group 34 First lens barrel 40 Second lens group holding member 42 Lock lever

Claims (7)

At least two object side lens groups located on the object side;
Located on the first optical axis, which is the optical axis of the object side lens group, bends the first optical axis and guides it to the second optical axis. A reflective optical element retracted along,
Of the object side lens group, a second lens group located on the reflective optical element side includes a drive frame that is driven and controlled along the first optical axis, and a lens holding frame that holds the second lens group. And consists of
The lens holding frame has a contact portion that is pressed and retracted by a first lens group located on the object side in the object side lens group in the non-photographing state. An imaging apparatus, wherein at least the second lens group is stored and retracted in a space formed by a frame and a rear portion of the lens holding frame and a space where the reflective optical element is located at the time of photographing.   The imaging apparatus according to claim 1, wherein a part of the lens holding frame is retracted to a space where the reflective optical element is located at the time of photographing.   The imaging apparatus according to claim 1, wherein the lens holding frame is connected to the drive frame by an elastic force.   The drive source for driving the first lens group and the drive source for driving the reflective optical element are the same, and the reflection is performed when the first lens group is moved along the first optical axis. The imaging apparatus according to claim 1, wherein there is a region where the optical element is not driven.   The drive source for driving the first lens group and the drive source for driving the reflective optical element are the same, and when the reflective optical element is driven along the second optical axis, The imaging apparatus according to claim 1, wherein there is a region where one lens group does not move along the first optical axis.   5. The lens holding frame and the drive frame are connected by an elastic force, and further include a restricting member that restricts movement in a direction in which the connection is released in a photographing state. The imaging device described in 1.   The image pickup apparatus according to claim 6, further comprising a release mechanism that releases the restriction by the restriction member when the photographing state shifts to the non-photographing state.

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