JP4993400B2 - Lens barrel and imaging device - Google Patents

Description

  The present invention relates to a retractable lens barrel, and more particularly to a lens barrel suitable for being retracted more thinly.

  Conventionally, a camera is a so-called collapsible type in which the distance between lens groups, which are optical elements constituting an imaging optical system, is reduced and stored thinly in order to make the camera more convenient when not used for shooting. Cameras that use this lens barrel have become common.

As this retractable lens barrel, a drive motor that drives the focusing lens is arranged in the lens barrel, and in order to avoid interference between the lens group lens frame and the drive motor that are retracting, a notch is formed in the lens group lens frame. There is disclosed a structure that is formed and thinned so as not to interfere with a lens group lens frame that is retracted when retracted (for example, see Patent Document 1).
JP 2003-287670 A

  However, the retracting of the lens barrel described in Patent Document 1 has a minute gap that does not interfere with components such as a lens frame and a shutter unit holding each lens group when the lens group is moved due to degeneration. Then, it is made to approach and move to the image plane side.

  In the collapsible method as described above, the thickness in the optical axis direction when retracted is determined by the dimensions in the optical axis direction of components such as a lens frame and a shutter unit holding each lens group. Have difficulty.

  In view of the above problems, an object of the present invention is to obtain a lens barrel capable of reducing the thickness in the optical axis direction when retracted, and to obtain a thinner imaging device.

  The above object is achieved by the invention described below.

1. In a lens barrel that has a plurality of lens groups and a plurality of lens frames for holding each of the lens groups, and moves the lens frames to extend and retract the lens groups,
The plurality of lens groups includes a first lens group and a second lens group arranged in order from the subject side,
The first lens group includes a plurality of lenses and is configured to change a lens interval.
The lens frame that holds the first lens group includes a biasing member that biases the lens in a direction that widens the lens interval in the first lens group, and a lens that is biased by the biasing member. A locking portion that is locked in position,
The lens frame holding the second lens group has a contact portion that contacts the lens frame portion of the first lens group locked by the locking portion,
When the first lens group and the second lens group come close to each other and the abutting part comes into contact, the lens locked by the locking part is resisted against the urging force of the urging member. A lens barrel configured to be moved so that the lens interval in the first lens group is shortened when retracted or zoomed .

2. The plurality of lens groups further includes a third lens group adjacent to the second lens group,
The second lens group includes a plurality of lenses and is configured to change a lens interval.
The lens frame that holds the second lens group includes a biasing member that biases the lens in a direction that widens the lens interval in the second lens group, and a lens that is biased by the biasing member. A locking portion that is locked in position,
The lens frame that holds the third lens group has a contact portion that contacts the frame portion of the lens of the second lens group locked by the locking portion,
When the second lens group and the third lens group come close to each other and the abutting portion comes into contact with each other, the urging member holds the lens of the second lens group locked by the locking portion. 2. The lens barrel according to 1, wherein the lens barrel is moved against the urging force to shorten a lens interval in the second lens group .

3. 3. The lens barrel according to 2 , wherein the lens interval in the second lens group is shortened when retracted .

4 . An imaging apparatus comprising the lens barrel according to any one of 1 to 3 .

  According to the present invention, even when the imaging optical system has the same configuration, it is possible to obtain a lens barrel having a thinner thickness in the optical axis direction when retracted, and further by providing this lens barrel. Thus, a thinner imaging device can be obtained.

  Hereinafter, the present invention will be described in detail with reference to embodiments, but the present invention is not limited thereto.

  FIG. 1 is an external view showing a camera 200 which is an example of an image pickup apparatus including a lens barrel according to an embodiment of the present invention. 3A is a perspective view of the front surface of the camera 200, and FIG.

  In FIG. 1A, reference numeral 100 denotes a lens barrel, which includes a zoom imaging optical system. Reference numeral 111 denotes a finder window, 112 denotes a release button, 113 denotes a flash light emitting unit, 114 denotes a light control sensor window, 115 denotes a strap attaching unit, and 116 denotes an external input / output terminal (for example, a USB terminal). Reference numeral 117 denotes a slide barrier. When the lens barrel 100 is opened, the lens barrel 100 is ready for photographing as shown in the figure, and the lens barrel 100 is retracted by moving it slightly in the closing direction. That is, the camera 200 is activated in conjunction with opening / closing of the slide barrier 117.

  The release button 112 performs a shooting preparation operation of the camera 200, that is, a focusing operation and a photometric operation, by pressing the first step, and a shooting exposure operation is performed by pressing the release button 112 by the second step.

  In FIG. 2B, 120 is a viewfinder eyepiece, 121 is a red and green display lamp, and displays AF and AE information to the photographer by lighting or blinking. A zoom button 122 is a button for zooming up and zooming down. Reference numeral 123 denotes a menu / set button, reference numeral 124 denotes a four-way switch, and reference numeral 125 denotes an image display unit which displays an image, other character information, and the like. The menu / set button 123 has a function of displaying various menus on the image display unit 125, selecting with the selection button 124, and confirming with the menu / set button 123. A reproduction button 126 is a button for reproducing the captured image. Reference numeral 127 denotes a display button, which is a button for selecting display or deletion of an image displayed on the image display unit 125 or other character information. Reference numeral 128 denotes an erase button, which is a button for erasing the photographed and recorded image. 129 is a tripod hole, 130 is a battery / card cover. Inside the battery / card cover 130, a battery for supplying power to the camera and a slot for a card for recording a photographed image are provided, and this is a card-type recording memory for recording a battery and an image. A memory card (not shown) can be inserted and removed.

  FIG. 2 is a cross-sectional view showing a state of the lens barrel 100 according to the present embodiment at the wide-angle end. A schematic configuration of the lens barrel 100 according to the present embodiment will be described with reference to FIG.

  In the figure, reference numeral 1 denotes a first lens group, which is composed of two lenses, a lens 1a and a lens 1b in this example. Reference numeral 2 denotes a second lens group, which is composed of two lenses, a lens 2a and a lens 2b in this example. Reference numeral 3 denotes a third lens group, which is a single lens in this example. An imaging optical system is formed by these three lens groups.

  Behind the imaging optical system, an optical filter F in which an infrared light cut filter and an optical low-pass filter are stacked and an imaging element 4 are disposed. Reference numeral 5 denotes a ground plane, which holds the optical filter F, the image sensor 4 and the like.

  A fixed drum 23 is fixed to the main plate 5. A cam cylinder 22 is disposed inside the fixed cylinder 23 and supported so as to be rotatable with respect to the fixed cylinder 23 and also movable in the direction of the optical axis O. A front cylinder 21 is disposed inside the cam cylinder 22.

  A rectilinear guide 31 is disposed inside the front tube 21, and the rectilinear guide 31 is integrally formed with an engagement plate that is engaged with a rectilinear guide groove formed in the fixed barrel 23 and is restricted in rotation. The cam cylinder 22 can move in the optical axis O direction together with the cam cylinder 22 as the cam cylinder 22 moves in the optical axis O direction without rotating.

  The first lens group 1 is held by a first lens group lens frame 11, and the first lens group lens frame 11 is supported by a front tube 21. In the front cylinder 21, the cam pin 21 p is engaged with a cam groove 22 m formed on the inner peripheral surface of the cam cylinder 22, and a part of the front cylinder 21 is engaged with the rectilinear guide 31. By rotating with respect to 23 and moving in the direction of the optical axis O, linear movement in the direction of the optical axis O is performed.

  The second lens group 2 is held by the second lens group moving lens frame 12. Although not shown, the second lens group moving lens frame 12 is partly engaged with the rectilinear guide 31 and integrally formed. The cam pin formed or implanted in the cam groove 22 is engaged with a cam groove formed on the inner peripheral surface of the cam barrel 22, and the cam barrel 22 rotates and moves in the optical axis O direction to move straight in the optical axis O direction. To do. An aperture shutter unit 16 is fixed to the second lens group moving lens frame 12. The aperture shutter unit 16 may have not only an aperture and a shutter but also an aperture only and a shutter only.

  The third lens group 3 is held by a third lens group frame 13, and this third lens group frame 13 is configured to be movable in the direction of the optical axis O during zooming and focusing by a stepping motor 14, and other lenses. It is designed to be driven independently of the group.

  The cam barrel drive gear 41 is rotated forward and backward by a motor (not shown) arranged outside the lens barrel, a reduction gear train, and a columnar gear, and the cam barrel drive gear 41 enables forward and reverse rotation of the cam barrel 22. ing.

  A cam pin 22p is integrally formed or implanted in the cam barrel 22, and is guided in a cam groove 23m formed on the inner peripheral surface of the fixed barrel 23 by the rotation of the cam barrel 22 in the direction of the optical axis O. It is movable. The cam groove on the inner peripheral surface of the cam cylinder 22 is formed of two types of cam grooves 22m that engage with the cam pins 21p formed on the front cylinder 21 and cam grooves (not shown) that engage with the second lens group frame 12. Thus, zooming is performed by moving the first lens group 1 and the second lens group 2 to desired positions, respectively.

  In the zooming operation by the lens barrel 100 shown in the figure, the cam barrel drive gear 41 is driven from the wide state shown in FIG. 1 by a motor (not shown), a reduction gear train and a columnar gear arranged outside the barrel. When the cam cylinder 22 is rotated with respect to the fixed cylinder 23, the front cylinder 21 is moved to a predetermined position by the cam groove 22m, the cam pin 21p and the rectilinear guide 31 formed on the inner peripheral surface of the cam cylinder 22. The second lens group moving lens frame 12 is brought into a predetermined position by a cam groove (not shown) formed on the inner peripheral surface of the cylinder 22, a cam pin (not shown) formed on the second lens group moving lens frame 12, and a straight guide 31. It is done by moving.

  Further, after that, the third lens group lens frame 13 is moved to a predetermined position by the stepping motor 14, and then focusing is performed.

  Next, a holding structure for the lens 1a and the lens 1b constituting the first lens group 1 held by the first lens group barrel 11 of the lens barrel 100 according to the present embodiment will be described.

  FIG. 3 is a cross-sectional view showing an example of the holding structure of the lens 1a and the lens 1b held by the first lens group lens frame 11. As shown in FIG. In addition, in the following figures, in order to avoid duplication of description, the same functional member will be given the same reference numeral.

  As shown in the figure, the lens 1a is fixed to the first lens group lens frame 11 by adhesion, press fitting, or the like. On the other hand, as shown in the figure, the lens 1b is pressed by the urging force of the compression coil spring 32, which is an urging member, and is fixed to the lens frame 33 locked by the locking portion 11k on the image plane side of the first lens group lens barrel 11. It is fixed by bonding or the like. In other words, the lens 1b is slidably positioned in the optical axis O direction by fitting the first lens barrel 11 and the lens frame 33 in the radial direction, and is illustrated in the figure by the urging force of the compression coil spring 32 in the optical axis O direction. Thus, the lens interval is maintained.

  Next, a holding structure for the lens 2a and the lens 2b constituting the second lens group 2 held by the second lens group barrel 12 of the lens barrel 100 according to the present embodiment will be described.

  FIG. 4 is a cross-sectional view showing an example of the holding structure of the lens 2a and the lens 2b held by the second lens group lens frame 12. As shown in FIG.

  As shown in the drawing, the lens 2a is fixed to the second lens group frame 12 by bonding, press-fitting, or the like. On the other hand, as shown in the drawing, the lens 2b is pressed by the urging force of the compression coil spring 34, which is an urging member, and is fixed to the lens frame 35 locked by the locking portion 12k on the image plane side of the second lens group lens frame 12. It is fixed by bonding or the like. That is, the lens 2b is positioned so as to be slidable in the optical axis O direction by fitting the second lens barrel 12 and the lens frame 35 in the radial direction. Thus, the lens interval is maintained.

  The lenses 1a, 1b, 2a, 2b, and 3 are described as a single lens in this example. However, a plurality of lenses may be cemented, and the number of components of each lens group is also different. Of course, it is not limited to this.

  FIG. 5 is a cross-sectional view showing a state when the lens barrel 100 according to the present embodiment is at the telephoto end due to zooming. 2A is a schematic sectional view showing the entire lens barrel 100, and FIG. 2B is an enlarged sectional view showing states of the first lens group 1 and the second lens group 2. FIG.

  To the telephoto end shown in FIG. 2A, the cam barrel drive gear 41 is driven from the wide angle end shown in FIG. 2 by a motor, a reduction gear train and a columnar gear (not shown). By rotating 22, the front cylinder 21 is moved to a predetermined position by the cam groove 22 m formed on the inner peripheral surface of the cam cylinder 22, the cam pin 21 p and the rectilinear guide 31, and is formed on the inner peripheral surface of the cam cylinder 22. The second lens group moving lens frame 12 is moved to a predetermined position by a cam groove (not shown), a cam pin (not shown) formed in the second lens group moving lens frame 12 and a rectilinear guide 31, and a third motor is moved by the stepping motor 14. This is done by moving the lens group 3 to a predetermined position.

  As shown in FIG. 4A, at the telephoto end, the first lens group 1 and the second lens group 2 are in close proximity.

  At this time, as shown in FIG. 5B, the protrusion 16t formed on the aperture shutter unit 16 fixed to the second lens group moving lens frame 12 comes into contact with the lens frame 33, and the compression coil spring 32 is attached. The lens frame 33 is moved toward the object side in the optical axis O direction against the force. Thereby, it will be in the state changed so that the space | interval of the lens 1b and the lens 1a may become narrow.

  In other words, at the telephoto end at the time of zooming, the distance between the lens 1a and the lens 1b held by the first lens group frame 11 is changed to be shortened. In this way, by configuring the distance between the lenses in the first lens group 1 held by the first lens group frame 11 to be shortened at the telephoto end, the degree of freedom in lens design can be increased. Imaging performance can be improved.

  FIG. 6 is a schematic cross-sectional view showing a state in which the lens barrel 100 according to the present embodiment is retracted. To the retracted state shown in the figure, the third lens group 3 is first moved toward the image sensor 4 by the stepping motor 14 from the wide-angle end position shown in FIG. The illustrated motor is rotated in the direction opposite to that when driven in the telephoto end direction, and the cam barrel 22 is rotated by the cam barrel drive gear 41.

  As shown in the figure, when the lens barrel 100 is retracted, the lens 1b held by the first lens group lens frame 11 is moved to the second lens group moving lens frame 12 as described in FIG. Due to the projection 16t formed on the aperture shutter unit 16 fixed to, the distance from the lens 1a is changed to be narrow.

  Further, in the lens 2 b held by the second lens group lens frame 12, the projection 35 t formed on the lens frame 35 abuts against the fixed diaphragm plate S of the third lens group 3, and the urging force of the compression coil spring 34. Against this, the lens frame 35 is moved toward the object side in the optical axis O direction. Thereby, it will be in the state changed so that the space | interval of the lens 2b and the lens 2a may become narrow.

  That is, when the lens barrel 100 of the present embodiment is retracted, the lens barrel 100 has a space that is a lens interval between the lens 1a and the lens 1b in the first lens group 1 held by the first lens group barrel 11. The lens space between the lens 2a and the lens 2b in the second lens group 2 held by the second lens group frame 12 is shortened and retracted. This makes it possible to retract the lens barrel thinner even when the photographing optical system is the same as the lens barrel thickness when retracting, which has been performed by shortening the space between the conventional lens groups. .

  As described above, the lens interval in the lens group held by each lens frame can be changed, and when retracting, not only the interval between the lens groups, but also the lens interval in the lens group. Also, it becomes possible to obtain a thinner lens barrel having a thickness in the optical axis direction when retracted. Further, by providing this lens barrel, a thinner imaging device can be obtained.

  In the above embodiment, the example in which the lens interval in the first lens group and the second lens group is shortened when retracted is described. However, the present invention may be applied to only one of them. Of course. In addition, the present invention can be applied to a lens group that degenerates on the optical axis in a lens barrel having a lens group that retracts out of the optical axis when retracted.

1 is an external view showing a camera which is an example of an imaging apparatus including a lens barrel according to an embodiment of the present invention. It is sectional drawing which shows the state at the time of the wide angle end of the lens barrel which concerns on this Embodiment. It is sectional drawing which shows an example of the holding structure of the lens 1a currently hold | maintained at the 1st lens group lens frame, and the lens 1b. It is sectional drawing which shows an example of the holding structure of the lens 2a currently hold | maintained at the 2nd lens group lens frame, and the lens 2b. It is sectional drawing which shows a state when the lens barrel which concerns on this Embodiment becomes a telephoto end by zooming. It is a schematic sectional drawing which shows the state at the time of retraction of the lens barrel which concerns on this Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st lens group 2 2nd lens group 3 3rd lens group 4 Image sensor 5 Ground plane 11 1st lens group frame 12 2nd lens group frame 13 3rd lens group frame 14 Stepping motor 16 Aperture shutter unit 21 Front Tube 22 Cam tube 23 Fixed barrel 31 Linear guide 41 Cam barrel drive gear 100 Lens barrel 200 Camera F Optical filter

Claims (4)

In a lens barrel that has a plurality of lens groups and a plurality of lens frames for holding each of the lens groups, and moves the lens frames to extend and retract the lens groups,
The plurality of lens groups includes a first lens group and a second lens group arranged in order from the subject side,
The first lens group includes a plurality of lenses and is configured to change a lens interval.
The lens frame that holds the first lens group includes a biasing member that biases the lens in a direction that widens the lens interval in the first lens group, and a lens that is biased by the biasing member. A locking portion that is locked in position,
The lens frame holding the second lens group has a contact portion that contacts the lens frame portion of the first lens group locked by the locking portion,
When the first lens group and the second lens group come close to each other and the abutting part comes into contact, the lens locked by the locking part is resisted against the urging force of the urging member. A lens barrel configured to be moved so that the lens interval in the first lens group is shortened when retracted or zoomed . The plurality of lens groups further includes a third lens group adjacent to the second lens group,
The second lens group includes a plurality of lenses and is configured to change a lens interval.
The lens frame that holds the second lens group includes a biasing member that biases the lens in a direction that widens the lens interval in the second lens group, and a lens that is biased by the biasing member. A locking portion that is locked in position,
The lens frame that holds the third lens group has a contact portion that contacts the frame portion of the lens of the second lens group locked by the locking portion,
When the second lens group and the third lens group come close to each other and the abutting portion comes into contact with each other, the urging member holds the lens of the second lens group locked by the locking portion. 2. The lens barrel according to claim 1, wherein the lens barrel in the second lens group is shortened by being moved against the urging force . The lens barrel according to claim 2 , wherein the lens interval in the second lens group is shortened when retracted . An imaging apparatus comprising the lens barrel according to any one of claims 1 to 3 .

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