JP2005274703A - Lens barrel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens barrel equipped with a focusing mechanism capable of adjusting a focal position without interfering with an image evaluation device, regulating the tilt of an optical axis, securing rigidity, fixing an optical lens and suitable for automatization. <P>SOLUTION: The lens barrel is equipped with a lens barrel base 3 having a base reference surface 3a and a base inner wall 3b which becomes a straight advance guide for a lens unit 5, a focusing part 4 having a reference surface 4a coming into contact with the reference surface 3a and a slope 4b, a lens barrel part 5a having a lens holding part 5b perpendicular to the reference surface 4a, a lens unit 5 having a slope 5d paired with the slope of the focusing part 4 and an outer wall 5e which becomes a straight moving guide, and a fixing means for fixing the focusing part 4 and the lens unit 5 in the lens barrel base 3. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a lens barrel provided with a focus adjustment mechanism that focuses an optical lens mounted on a camera or a camera-equipped mobile device on an image sensor.

  FIG. 10 shows a configuration of a conventional apparatus having a focus adjustment mechanism. The lens holding portion 105 holding the optical lens 106 on the lens holding portion inner surface 105a and having the male screw 105b is screwed to the lens barrel base 103 having the female screw 103a fixed to the substrate 101 on which the image sensor 102 is mounted. A focus adjustment mechanism is known in which a rotational force around an axis is applied to a holding unit 105 to cause the image pickup element 102 to focus on the optical lens 106 (see, for example, Patent Document 1).

When the focus position is adjusted by the above-described focus adjustment mechanism, the image evaluation device 9 is disposed opposite to the optical lens 106 on the extension line of the optical axis passing through the centers of the image sensor 102 and the optical lens 106, and image evaluation is performed. While observing the output state of the apparatus 9, the lens holding unit 105 is screwed to adjust the focal position of the optical lens 106 on the image sensor 102.
JP-A-8-101333

  The lens holding unit, which is a focus adjustment mechanism that rotates the optical lens to focus on the image sensor, and the image evaluation device are on the same axis. Therefore, when trying to automate the focus adjustment process, the back of the zoom lens barrel is particularly important. When automating the focus adjustment process, there is a problem that it is difficult to configure a mechanism for rotating the lens holding portion.

  In addition, it is necessary to fix the lens holding part by means such as adhesion after focus adjustment, but in this case as well, in order to avoid interference with the image evaluation apparatus on the same axis, the fixing work is performed after moving to another place. For this reason, there is a possibility that the position of the lens holding portion is shifted during the movement.

  In addition, since the screw is used in the portion directly related to the accuracy of the focal position, the optical axis of the optical lens may be tilted with respect to the image sensor due to the processing accuracy of the male screw and the female screw. there were.

  In addition, since the lens holding part is fixed to the lens barrel base only by a threaded part, there is a disadvantage that the rigidity is low.

  An object of the present invention is to provide high rigidity while performing focus adjustment without interfering with an image evaluation apparatus disposed opposite to an optical lens, and without tilting the optical axis of the optical lens with respect to an image sensor. An object of the present invention is to provide a lens barrel having a focus adjusting mechanism capable of fixing the lens barrel base and the lens unit while securing the lens barrel.

  In order to solve the above-described problems, the present invention moves a lens unit holding an optical lens in the optical axis direction of the optical lens, and focuses a subject on the photosensitive surface of the image sensor. In a lens barrel having a focus adjustment mechanism for forming an image, a mirror having a reference plane parallel to the imaging surface and a rectilinear guide portion perpendicular to the reference surface and fixed to a substrate on which the imaging element is mounted A tube base, a focus adjustment unit that is slidably installed on a reference surface of the lens barrel base and has an inclined surface that is inclined with respect to the sliding surface on the opposite side of the sliding surface, and a pair of the inclined surface A lens unit comprising a lens barrel support portion having a rectilinear guide portion paired with an inclined surface and a rectilinear guide portion of the lens barrel base, and a lens barrel portion holding an optical lens, and the lens unit as the lens barrel base Fixing And stage, constituting the lens barrel to include a focus adjustment mechanism comprising: a fixing device which fixes the focusing unit in the lens barrel base.

  In the present invention, the direction in which the inclined surface of the focus adjusting unit and the inclined surface of the lens unit slide is the X axis, the direction orthogonal to the X axis on the lens barrel base reference surface is the Y axis, and the optical axis direction of the optical lens is Z. When the coordinate system is configured as an axis, in the present invention, the lens unit holding the optical lens is moved in the Z direction by moving the focus adjustment unit in the X direction, and the focus adjustment of the optical lens on the image sensor is performed. In addition, the focus adjustment unit and the lens unit can be fixed to the lens barrel base from the Y direction. As a preferred form of the fixing means, the lens barrel is configured so as to fix the lens barrel base and the focal position adjusting unit and the lens barrel base and the lens unit using male screws.

  Further, the present invention provides a focus adjustment in which a lens unit holding an optical lens is moved in the optical axis direction of the optical lens, and an object focused by the optical lens is focused on the photosensitive surface of the image sensor. A lens barrel base having a mechanism, having a reference plane parallel to the imaging surface and a rectilinear guide portion perpendicular to the reference surface, and fixed to a substrate on which the imaging device is mounted; and a reference surface of the lens barrel base A focus adjusting unit having an inclined surface inclined with respect to the sliding surface on the opposite side of the sliding surface, an inclined surface paired with the inclined surface, and a straight guide portion of the lens barrel base In a lens barrel comprising a lens barrel support portion having a straight guide portion and a lens unit including a lens barrel portion holding an optical lens, a fitting hole formed in a side wall surface of the barrel base is provided. The tip through the focal point A feed screw that contacts the node and moves the focus adjustment unit; an elastic member that urges the lens unit toward the imaging element in the optical axis direction; and an elastic member holding plate that holds the elastic member. The lens barrel is configured to include a focus adjustment mechanism that adjusts the position of the lens unit in the optical axis direction according to the rotation direction and rotation angle of the screw.

  In the present invention, it is possible to adjust the focal position by rotating the feed screw without fixing the lens barrel base, the focus adjusting unit, and the lens unit with the fixing means. In this configuration, there is an advantage that the focal position can be changed relatively easily when the out-of-focus condition occurs or when the focus is set at a relatively short distance.

  The present invention also includes a rotatable cam cylinder having a gear and a cam groove, a rectilinear guide cylinder having a rectilinear guide groove formed of a slit-like opening parallel to the optical axis, and a rectilinear guide groove of the rectilinear guide cylinder. A cam follower that engages with a cam groove of the cam cylinder, and is disposed on an inner peripheral side of the rectilinear guide cylinder and holds an optical lens; an inner peripheral side of the rectilinear guide cylinder; A zoom lens barrel including a second zoom lens unit that is disposed closer to the image sensor than the first zoom lens unit and holds an optical lens, and includes the focus adjustment mechanism according to claim 1. A lens barrel is constructed.

  In the present invention, by using the focus adjustment mechanism using the wedge-shaped focus adjustment unit for the back focus adjustment of the zoom lens barrel, it is possible to perform high-precision focus adjustment without rotating the optical lens.

  According to the present invention, for the purpose of focus adjustment, the X axis + direction is used for focus adjustment by moving the focus adjustment unit in a state where the image evaluation device is arranged in the direction opposite to the optical lens that is the Z axis + direction. Since the Y axis ± direction can be used for fixing the focus adjustment unit and the lens unit, the focus adjustment and the focus adjustment unit and the lens unit can be fixed in the same station, which facilitates automation.

  In addition, if the inclined surface of the focus adjustment unit and the inclined surface of the lens unit are brought into contact with each other and the lens holding unit is perpendicular to the reference surface in a state where the focus adjustment unit and the lens unit are combined, high accuracy can be achieved. With this, the inclination of the optical axis can be reduced.

  In addition, since the reference surface of the lens barrel base, the reference surface of the focus adjusting unit, and the inclined surface of the focus adjusting unit and the inclined surface of the lens unit are in surface contact with each other and fixed in that state, the lens barrel has high rigidity. can get.

A focus adjustment mechanism according to an embodiment of the present invention will be described with reference to FIGS.
The focus adjustment mechanism according to the embodiment of the present invention shown in FIGS. 1 and 2 includes a printed circuit board 1 on which peripheral circuits such as an image processing circuit mounted with an image pickup device 2 are formed, and is fixed to the printed circuit board 1. A lens barrel base 3, a focus adjustment unit 4 disposed on the lens barrel base 3 so as to be slidable in the X direction of the coordinate axis in the drawing, and an optical lens 6 are held, and can slide in the Z direction of the coordinate axis in the drawing. The arranged lens unit 5 and the lens unit 5 are fixed to the lens barrel base 3. A lens unit fixing screw 7 and a focus adjusting unit fixing screw 8 for fixing the focus adjusting unit 4 to the lens barrel base 3 are provided. The lens barrel base 3 has a U-shape, a reference surface 3a of the lens barrel base parallel to the imaging surface of the image sensor 2, and an inner wall 3b of the three lens barrel bases perpendicular to the reference surface 3a of the lens barrel base. And a longitudinally elongated hole 3c that is far from the opening on the two surfaces that form the U-shaped opening, and a horizontally elongated hole 3d that is closer to the opening on the two surfaces that form the U-shaped opening. .

  The focus adjustment unit 4 has a U-shape, and the focus adjustment unit converts the movement in the X direction of the reference axis 4a of the focus adjustment unit in contact with the lens barrel base reference surface 3a of the lens barrel base 3 and the coordinate axis in the figure into the Z direction. And a female screw 4c for fixing the focus adjusting unit to the lens barrel base.

  The lens unit 5 is a lens unit having a cylindrical shape and a lens holding frame 5 a having a lens holding portion 5 b for holding the optical lens 6 on the inner surface, and a female screw 5 f for fixing the lens unit 5 to the barrel base 3. An inclined surface 5d of the lens unit that is paired with the inclined surface 4b of the lens barrel support portion 5c and the focus adjusting portion and moves the coordinate axis in the Z direction in the figure, and the inner wall 3b of the lens barrel base when moving in the Z direction. It is comprised from the outer wall 5e of the lens unit slidably installed. The lens holding unit 5b is perpendicular to the reference surface 4a of the focus adjusting unit with the lens unit 5 and the focus adjusting unit 4 in contact with the inclined surface 5d of the lens unit and the inclined surface 4b of the focus adjusting unit. When processed, the tilt of the optical axis can be regulated with high accuracy.

  Next, the focus adjustment operation will be described with reference to FIGS. In order to obtain a high quality photographed image using the image pickup device 2 such as a CCD or CMOS image sensor, the subject is focused by the optical lens 6 and focused on the photosensitive surface of the image pickup device 2 to form an image. is important. In order to obtain a correctly focused image, the image evaluation device 9 is set as a subject facing the optical lens 6 and the reference surface 4a of the focus adjusting unit 4 is shown on the reference surface 3a of the lens barrel base. It is slid in the X direction of the middle coordinate axis, and converted into movement in the Z direction by the inclined surface 4b of the focus adjusting unit 4 and the inclined surface 5d of the lens unit 5, and the inner wall 3b of the lens barrel base and the outer wall of the lens unit A lens unit that evaluates the state of the photographed image while moving the optical lens 6 in the Z direction of the coordinate axis in the drawing by moving the lens unit 5 with 5e as a straight guide, and holding the optical lens 6 at the optimum position of the photographed image 5 is fixed to the lens barrel base 3 with a lens unit fixing screw 7 that passes through the vertically long hole 3 c of the lens barrel base 3.

  Further, by fixing the focus adjusting unit 4 to the lens barrel base 3 with the focus adjusting unit fixing screw 8 that passes through the laterally long hole 3d of the lens barrel base 3, the rigidity of the mounting portion of the lens unit 5 is improved. In this embodiment, the lens barrel base inner wall 3b and the lens unit outer wall 5e are used as a guide for moving the lens unit 5 in the Z direction in the drawing. Is also possible.

  In the present embodiment, the focus adjusting unit fixing screw 8 and the lens unit fixing screw 7 are used as fixing means for the focus adjusting unit 4 and the lens unit 5 with respect to the lens barrel base 3, but the fixing unit is limited to screws. For example, it is also possible to use an adhesive as a fixing means. As shown in FIG. 6, instead of the vertically long hole 3c and the horizontally long hole 3d of the lens barrel base 3, an adhesive injection hole 3e is formed to fix the lens unit, the lens barrel base, the focus adjusting unit, and the lens barrel base. An appropriate amount of the adhesive 10 is injected from the adhesive injection hole 3e and fixed. In addition, since it is necessary to fix the lens barrel base 3, the focus adjustment unit 4, and the lens unit 5 in a short time after setting the focal position, it is desirable to use a photo-curing adhesive.

  Next, the configuration of a lens barrel provided with a focus adjustment mechanism suitable for automating the focus adjustment process will be described with reference to FIG. FIG. 7 shows that the wedge-shaped focus adjustment unit is moved in the X-axis direction using a feed screw, and the lens unit is moved in the Z-axis + direction by using the inclined surface of the focus adjustment unit and the lens unit. On the other hand, it is a perspective view of a focusing mechanism that moves the lens unit in the Z-axis direction using the biasing force of the elastic material.

  The lens barrel having the focus adjustment mechanism shown in FIG. 7 includes a lens unit 5, a focus adjustment feed screw 11, an elastic member 12, a lens barrel base 13, a focus adjustment unit 14, an elastic member holding unit 15, and an elastic member holding unit. A fixing screw 16 is provided. The lens unit 5 has the same configuration as the lens unit shown in FIG. The focus adjustment feed screw 11 has a function of moving the focus adjustment unit 14 in the X-axis direction by bringing the tip portion into contact with the end surface of the focus adjustment unit. The elastic member 12 has a function of urging the lens unit 5 in the Z-axis direction. The lens barrel base 13 is the same as the lens barrel base 3 shown in FIG. Consists of configuration. The focus adjustment unit 14 has a configuration in which the female screw 4c is omitted from the focus adjustment unit 4 shown in FIG. The elastic member holding plate 15 has a function of pressing and holding the elastic member 12, and after the elastic member 12 is housed in a space formed by the lens barrel base 13 and the lens tube support portion 5c of the lens unit, the elastic member 12 12 is fixed to the lens barrel base 13 with an elastic member holding plate fixing screw 16 so as to be pressed.

  Next, the focus adjustment operation by the rotation of the focus adjustment feed screw 11 will be described. When the focus adjustment feed screw 11 is rotated in the clockwise direction, the tip portion protrudes in the Y axis + direction, the focus adjustment portion 14 slides in the X axis − direction, the inclined surface of the focus adjusting portion and the inclined surface of the lens unit. , The lens unit 5 moves in the Z axis + direction. On the other hand, when the focus adjustment feed screw 11 is rotated counterclockwise, the tip of the focus adjustment feed screw 11 is moved to the focus adjustment portion 14 by the urging force of the elastic member 12 in the Z-axis direction with respect to the lens unit 5. The focus adjustment unit moves in the X axis + direction. The contacting lens unit moves in the Z-axis direction so that the inclined surface of the lens barrel holding portion 5b contacts the inclined surface of the focus adjusting portion 14. Accordingly, the position of the lens unit in the optical axis direction can be adjusted by the rotation direction and the rotation angle of the focus adjustment feed screw 11, and finally the focus position of the optical lens is optimized based on the output of the image evaluation device 9. Is possible. The elastic member 12 in the lens barrel only needs to have a function of urging the lens unit in the optical axis direction, and a rubber or resin plate-like material, or a spring such as a leaf spring or a coil spring can be used. It is.

  Finally, a configuration in which a focus adjustment mechanism that is a part of the present invention is applied to a zoom lens barrel that drives a plurality of lens groups using a cam barrel will be described with reference to FIGS. FIG. 8 is an exploded perspective view of a zoom lens barrel provided with a focus adjustment mechanism, and FIG. 9 is a longitudinal sectional view of the zoom lens barrel provided with a focus mechanism. The zoom lens barrel 21 includes a cam barrel 22, a first zoom lens unit 24, a second zoom lens unit 25, a plurality of first cam followers 26, a plurality of second cam followers 27, a lens unit stopper 28, and a lens barrel. A cover 29, an annular cam tube reinforcing member 30 that reinforces the cam tube, a first lens group 31 including, for example, an L1 lens, a second lens group 32 including a plurality of lenses L2, L3, a first lens, and a second lens, for example. A biasing spring 33 and an image sensor 37 that bias the units so as to repel each other are provided. As a focus adjusting mechanism, a linear guide groove 23a, a guide tube support portion 23c having a wedge shape, and a third lens portion 34 on the inner surface are provided. A linear guide tube 23 including a lens holding portion 23b to be held, a focus adjustment portion 35, and a lens barrel base 36 are provided. The cam cylinder 22 drives the first lens unit 24 via the cam groove 22a and the first cam follower 26, and drives the second lens unit 25 via the cam groove 22b and the second cam follower 27. . A gear 22c that receives a rotational driving force by a motor (not shown) is provided on the outer periphery of the cam cylinder.

  The rectilinear guide tube 23 has an opening therein, includes the first and second zoom lens units 24 and 25, and includes an insertion port into which the first and second cam followers 26 and 27 are fitted at one end. In order for the first and second lens units to move linearly along the optical axis direction, a plurality of linear guide grooves 23a composed of straight slit-shaped openings along the optical axis direction are formed on the inner peripheral surface and the outer periphery of the linear guide tube. It is formed so as to penetrate the surface.

  The first and second zoom lens units 24 and 25 each include a lens holding frame, and the first and second lens holding frames have a plurality of first and second cam followers 26 and 27 projecting from the outer peripheral portion. Then, the first and second lens groups 31 and 32 constituting the photographing lens system are held inside the first and second lens holding frames 24a and 25a, respectively.

  The first cam follower 26 is engaged with the first cam groove 22a of the cam cylinder 22 and the rectilinear guide groove 23a of the rectilinear guide cylinder 23, and the rotation of the cam cylinder 22 and the rectilinear guide groove 23a of the rectilinear guide cylinder 23a. Due to the restriction, the first zoom lens unit 24 is moved forward and backward along the optical axis direction together with the first zoom lens unit 24. Similarly, the second cam follower 26 is engaged with the cam groove 22b and the rectilinear guide groove 23a, and the second zoom lens is controlled by the rotation of the cam cylinder 22 and the restriction by the rectilinear guide groove 23a of the rectilinear guide cylinder. The unit 25 is moved forward and backward along the optical axis direction. The first and second cam followers are formed of metal, resin, or the like, and are respectively formed integrally with the first and second zoom lens units, or are preliminarily attached to the first and second lens units by press-fitting or the like. It is fixed.

  On the other hand, the focus adjustment mechanism includes a rectilinear guide tube 23 including a wedge-shaped guide tube support 23c, a third lens unit 34, a wedge-shaped focus adjustment unit 35, a lens barrel base 36, and an image sensor 37. By this focus adjustment mechanism, the rectilinear guide tube 23 that holds the third lens portion 34 inside the guide tube, together with the first lens unit 24 and the second lens unit 25 included in the cam tube 22 and the cam tube. It is arranged so as to be movable in the optical axis direction. Use the image evaluation device to detect the contrast based on the signal output from the image sensor, adjust the focus position to obtain an appropriate back focus position, and then use fixing means such as screws and adhesives. The focus adjustment of the zoom lens barrel can be realized relatively easily by fixing the straight guide tube, the focus adjustment unit, and the lens barrel base.

  Instead of the focus adjustment mechanism of the zoom lens barrel shown in FIG. 8, a focus adjustment mechanism using a feed screw and an elastic member shown in FIG. 7 can be used. Finally, the lens barrel shown in FIG. 1 and FIG. 7 and the zoom lens barrel shown in FIG. 8 use an image sensor. However, film cameras using a film instead of the image sensor are also used. It is also possible to use a lens barrel and a zoom lens barrel including the focus adjustment mechanism of the present invention.

It is a perspective view which shows the focus adjustment mechanism which concerns on embodiment of this invention. It is a disassembled perspective view which shows the focus adjustment mechanism of FIG. 1 in detail. It is a top view which shows the focus adjustment mechanism of FIG. It is sectional drawing which shows a focus adjustment mechanism along the arrow AA line of FIG. It is sectional drawing which shows a focus adjustment mechanism along the arrow BB line of FIG. It is a perspective view which shows the focus adjustment mechanism which uses the adhesive agent as a fixing method. It is a disassembled perspective view which shows the focus adjustment mechanism using a feed screw and an elastic member. It is a disassembled perspective view which shows the zoom lens barrel provided with a focus adjustment mechanism. It is a longitudinal cross-sectional view which shows the zoom lens barrel containing the focus adjustment mechanism of FIG. It is sectional drawing which shows the conventional back focus adjustment mechanism.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Printed circuit board 2 Imaging element 3 Lens barrel base 4 Focus adjusting part 5 Lens unit 6 Optical lens 7 Lens unit fixing screw 8 Focus adjusting part fixing screw 9 Image evaluation apparatus 10 Adhesive 11 Feed screw 12 Elastic material 13 Lens barrel base 14 Focus Adjustment unit 15 Elastic material holding plate 16 Fixing screw for elastic member holding plate 21 Zoom lens barrel 22 Cam barrel 23 Linear guide barrel 24 First lens unit 25 Second lens unit 26 First cam follower 27 Second cam follower 28 Lens unit stopper 29 Lens barrel cover 30 Cam barrel reinforcing ring 31 First lens group 32 Second lens group 33 Biasing spring 101 Printed circuit board 102 Imaging element 103 Base 105 Lens holding portion 105a Lens holding portion inner surface 106 Optical lens

Claims (5)

In a lens barrel having a focus adjustment mechanism that moves a lens unit holding an optical lens in the optical axis direction of the optical lens and forms an image on a predetermined imaging surface,
A lens barrel base having a reference surface parallel to the imaging surface and a rectilinear guide portion perpendicular to the reference surface;
A focus adjusting unit having an inclined surface inclined with respect to the sliding surface on the opposite side to the sliding surface sliding with respect to the reference surface of the lens barrel base;
A lens unit including a lens barrel support unit having an inclined surface paired with the inclined surface, a linear guide part of the lens barrel base, and a linear guide part paired with the lens base, and a lens holding frame holding an optical lens;
Fixing means for fixing the lens unit to the barrel base;
A lens barrel including a focus adjustment mechanism including a fixing means for fixing the focus adjustment unit to the lens barrel base.   2. The lens barrel according to claim 1, wherein a male screw is used as a fixing means for fixing the lens unit or the focus adjusting unit to the lens barrel base.   2. The lens barrel according to claim 1, wherein an adhesive is used as a fixing means for fixing the lens unit or the focus adjusting unit to the lens barrel base. A focus adjustment mechanism for moving the lens unit holding the optical lens in the optical axis direction of the optical lens to form an image on a predetermined imaging surface, and a reference surface parallel to the imaging surface and perpendicular to the reference surface A lens barrel base having a rectilinear guide portion; a focus adjusting unit having an inclined surface inclined with respect to the sliding surface on the side opposite to the sliding surface sliding with respect to a reference surface of the lens barrel base; A lens barrel comprising: an inclined surface paired with a surface; a lens barrel support portion having a straight guide portion paired with the lens barrel base; and a lens unit comprising a lens holding frame holding an optical lens; In
A feed screw that moves the tip portion in contact with the focus adjustment unit through an insertion hole formed in the side wall surface of the lens barrel base; and an elastic member that urges the lens unit toward the focus adjustment unit; An elastic member holding plate for holding the elastic member;
A lens barrel including a focus adjustment mechanism that adjusts the position of the lens unit in the optical axis direction according to the rotation direction and rotation angle of the feed screw. A rotatable cam cylinder having a gear and a cam groove;
A rectilinear guide tube having a rectilinear guide groove formed of a slit-like opening parallel to the optical axis;
A first zoom lens unit having a straight follower guide groove of the straight advance guide cylinder and a cam follower engaged with the cam groove of the cam cylinder, disposed on the inner peripheral side of the straight advance guide cylinder, and holding an optical lens;
A second zoom lens unit that is disposed on the inner peripheral side of the linear guide tube and on the lens barrel base side of the first zoom lens unit, and holds an optical lens;
5. A zoom lens barrel comprising the focus adjustment mechanism according to claim 1.

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