JP2016109804A - Lens unit and optical device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens holding structure which can accurately hold a lens and is excellent in impact resistance.SOLUTION: A lens unit includes a first lens 1, a lens holder 3 to which the back side of the first lens 1 is fitted and fixed, and a pressing member 4 provided on the front side of the first lens 1 and fixed to the lens holder 3 while pressing the first lens 1 against the lens holder 3. The pressing member 4 includes: a pressing part 4b which can be elastically deformed and presses the first lens 1 against the lens holder 3 when the pressing member 4 is fixed to the lens holder 3; and a restriction surface 4d which is arranged in the vicinity of the pressing part 4b with a gap in the optical axis direction between the first lens 1 and itself and restricts the floating of the first lens 1 in the optical axis direction.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a lens member constituting a photographing optical system of a lens barrel, a lens barrel including the lens member, and an optical apparatus such as a digital camera equipped with the lens barrel.

  As a lens barrel mounted on an optical device such as a digital camera, a zoom lens that changes the shooting magnification by moving a plurality of lenses constituting the shooting optical system in the optical axis direction between the storage position and the shooting position There is.

  In a zoom lens barrel, it is necessary to hold a plurality of lenses in a state where rotation is restricted with high accuracy and to move in the optical axis direction. In many cases, a plurality of lenses are held with respect to one lens holder.

  For example, a structure has been proposed in which an outer peripheral portion of a glass lens is fitted and held in a recess formed in a plastic lens in the optical axis direction (Patent Document 1). In addition, a structure has been proposed in which a tapered convex portion formed on the other plastic lens is fitted and held in the optical axis direction with a tapered concave portion formed on one of the two plastic lenses (patent). Reference 2).

US Pat. No. 6,0819,508 Japanese Patent No. 4959183

  By the way, when a lens is fixed using an adhesive, there is a problem that the surface accuracy of the lens surface is changed due to shrinkage due to curing of the adhesive and the holding accuracy is lowered, and this problem is particularly noticeable in a plastic lens. It is easy to occur. Therefore, how to fix the lens is important from the viewpoint of lens holding accuracy.

  However, the above-mentioned Patent Document 1 does not disclose or suggest how to fix the lens. On the other hand, in Patent Document 2, a plurality of lenses are pressed in the optical axis direction by lid members arranged on both sides in the optical axis direction of the plurality of lenses. It is difficult to solve the problem.

  Accordingly, an object of the present invention is to provide a lens holding structure that can hold a lens with high accuracy and is excellent in impact resistance.

  In order to achieve the above object, the present invention provides a first lens, a lens holder to which a back side of the first lens is fitted and fixed, and a front side of the first lens. A pressing member that is fixed to the lens holder in a state of being pressed toward the lens holder, and the pressing member includes the first lens when the pressing member is fixed to the lens holder. An elastically deformable pressing portion that presses against the holder and a clearance in the optical axis direction between the first lens and the first lens in the vicinity of the pressing portion, and the first lens is lifted in the optical axis direction And a restricting surface for restricting.

  ADVANTAGE OF THE INVENTION According to this invention, while being able to hold | maintain a lens with high precision, the lens holding structure excellent in impact resistance can be provided.

(A) is the perspective view which looked at the digital camera which is an example of the embodiment of the optical apparatus carrying the lens barrel which is an example of the lens unit of this invention from the front side (object side), (b) is (a) It is the figure which looked at the digital camera shown to) from the back side. FIG. 2 is a control block diagram of the digital camera shown in FIG. 1. It is sectional drawing in the storage position of a lens-barrel. It is sectional drawing in the imaging position of a lens-barrel. (A) is sectional drawing of the 5 group lens holder of the state holding the focus lens group, (b) is the S section expanded sectional view of (a). It is the perspective view which looked at the 5th group lens holder of the state holding the focus lens group from the front side. It is the disassembled perspective view which looked at the 5th group lens holder of the state holding the focus lens group from the front side. It is the disassembled perspective view which looked at the 5th group lens holder of the state holding the focus lens group from the back side. It is the perspective view which looked at the press member from the back side.

  Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1A is a perspective view of a digital camera as an example of an embodiment of an optical apparatus equipped with a lens barrel that is an example of a lens unit of the present invention, as viewed from the front side (subject side), and FIG. ) Is a view of the digital camera shown in FIG.

  As shown in FIG. 1A, a digital camera 23 according to this embodiment includes a finder 21 for determining the composition of a subject, an auxiliary light source 20 for performing photometric distance measurement, a strobe device 22, and a lens barrel on the front side. 16 is provided. The lens barrel 16 is of a zoom type in which a plurality of lenses constituting the photographing optical system are moved in the optical axis direction between the storage position and the photographing position to change the photographing magnification.

  On the upper surface side of the digital camera 23, a release button 17, a power switch button 19, and a zoom switch 18 are provided. As shown in FIG. 1B, operation buttons 26 to 31, a display 25 such as an LCD, and a viewfinder eyepiece 24 are provided on the back side of the digital camera 23.

  FIG. 2 is a control block diagram of the digital camera 23 shown in FIG. The bus 42 includes a CPU 44, ROM 43, RAM 45, release button 17, operation buttons 26 to 31, display 25, power switch button 19, zoom switch 18, memory 38, compression / decompression unit 39, memory card drive 40, and drive circuit 41. Connected.

  The drive circuit 41 includes a zoom mechanism 32 that zooms the lens barrel 16, a focus drive mechanism 46 that drives the focus lens groups 1 and 2, a shutter drive mechanism 33 that drives the shutter 9a, and an aperture drive mechanism that drives the aperture 9b. 34 is connected. The drive circuit 41 is connected to the image sensor 15 such as a CCD sensor or a CMOS sensor and the strobe device 22. Driving of each unit connected to the drive circuit 41 is controlled via the drive circuit 41 based on a signal from the CPU 44.

  Various control programs and the like are stored in the ROM 43, and data necessary for the various control programs is stored in the RAM 45. The analog signal processing unit 35 performs analog processing on the image data output from the image sensor 15 and outputs the analog data to the A / D conversion unit 36.

  The A / D conversion unit 36 converts analog data taken from the image sensor 15 into digital data and outputs the digital data to the digital signal processing unit 37. The digital signal processing unit 37 performs a predetermined process on the digital data converted by the A / D conversion unit 36 and outputs it to the memory 38 as image data.

  The image data stored in the memory 38 is subjected to compression processing such as JPEG or TIFF by the compression / decompression unit 39, and is then output to and stored in a memory card attached to the memory card drive 40.

  Further, the image data stored in the memory 38 and the image data stored in the memory card drive 40 can be expanded by the compression / decompression unit 39 and then displayed on the display 25 via the bus 42.

  Next, the lens barrel 16 will be described in detail with reference to FIGS. FIG. 3 is a cross-sectional view of the lens barrel 16 at the storage position. FIG. 4 is a cross-sectional view of the lens barrel 16 at the photographing position.

  As shown in FIGS. 3 and 4, the lens barrel 16 has a first group barrel 6 that holds the first group lens 5. A second group lens holder 8 for holding the second group lens 7 is disposed on the back side of the first group lens barrel 6, and a shutter 9 a and a diaphragm 9 b are integrally formed on the back side of the second group lens holder 8. An aperture shutter 9 is disposed.

  A third group lens holder 10a that holds the third group lens 10 is disposed on the back side of the aperture shutter 9, and a fourth group lens holder 11a that holds the fourth group lens 11 on the back side of the third group lens holder 10a. Is arranged.

  A fifth group lens holder 3 that holds the focus lens groups 1 and 2 is disposed on the back side of the fourth group lens holder 11 a, and an element holder 14 that holds the imaging element 15 is disposed on the back side of the fifth group lens holder 3. Has been placed.

  The focus drive mechanism 46 has a screw shaft 46b that is rotationally driven by a motor 46a, and a rack 3d provided on the outer periphery of the fifth group lens holder 3 is screwed to the screw shaft 46b. Therefore, when the screw shaft 46b is rotationally driven by the motor 46a, the fifth group lens holder 3 moves in the optical axis direction integrally with the focus lens groups 1 and 2, and a focusing operation is performed.

  A cam cylinder 12 is arranged on the outer peripheral side of the fixed cylinder 13, and a follower provided on the inner peripheral part of the first group barrel 6 follows a cam groove formed on the outer peripheral part of the cam cylinder 12. Yes.

  A straight advance key 13 a is provided at the front end (subject side) of the fixed barrel 13, and the straight advance key 13 a is engaged with a straight advance groove 6 a formed in the inner peripheral portion of the first group barrel 6. . As a result, when the cam barrel 12 rotates, the first group barrel 6 moves forward and backward in the optical axis direction while the follower of the inner peripheral portion follows the cam groove of the cam barrel 12 in a state where the rotation of the first group barrel 6 is restricted by the straight advance key 13a. To do.

  A plurality of cam grooves are formed in the inner periphery of the cam cylinder 12, and the plurality of cam grooves are formed in the second group lens holder 8, the aperture shutter 9, the third group lens holder 10a, and the fourth group lens holder 11a. Each provided follower follows.

  The rotation of the second group lens holder 8 is restricted by a fixed cylinder 13, and the aperture shutter 9, the third group lens holder 10a, and the fourth group lens holder 11a are arranged on a guide bar (not shown) provided on the fixed cylinder 13. Rotation is restricted by engaging.

  FIG. 5A is a cross-sectional view of the fifth group lens holder 3 in a state where the focus lens groups 1 and 2 are held, and FIG. 5B is an enlarged cross-sectional view of a portion S in FIG. FIG. 6 is a perspective view of the fifth group lens holder 3 in a state where the focus lens groups 1 and 2 are held as seen from the front side. FIG. 7 is an exploded perspective view of the fifth group lens holder 3 in a state where the focus lens groups 1 and 2 are held as seen from the back side. FIG. 8 is an exploded perspective view of the fifth group lens holder 3 in a state where the focus lens groups 1 and 2 are held as seen from the front side.

  As shown in FIGS. 5 to 8, the focus lens groups 1 and 2 include a first lens 1 disposed on the front side (upper side in FIG. 5) and a second lens disposed on the back side of the first lens 1. It is comprised by 2. In the present embodiment, both the first lens 1 and the second lens 2 are formed of a plastic mold lens.

  On the back side of the first lens 1, a short cylindrical fitting holding portion 1 a is provided substantially coaxially so as to be located radially inward from the outer peripheral portion of the first lens 1. The second lens 2 is fitted to the first lens 1 in the optical axis direction on the inner peripheral portion of the fitting holding portion 1a. Thereby, highly accurate axis alignment of the 1st lens 1 and the 2nd lens 2 is attained. In order to provide the first lens 1 with the fitting holding portion 1a into which the second lens 2 is fitted, it is advantageous in processing that the first lens 1 is formed of a plastic mold rather than a glass lens.

  As shown in FIG. 5, the fifth lens group holder 3 is formed with an annular holding recess 3a for holding the back side of the second lens 2 around the optical aperture. Further, the outer peripheral portion of the first lens 1 is fitted and fixed to the inner peripheral portion of the fifth group lens holder 3 located on the front side of the holding concave portion 3a.

  By fitting and fixing the first lens 1 to the fifth group lens holder 3, the second lens 2 integrated with the first lens 1 is held in the holding recess 3a. In this state, the second lens 2 and the first lens 1 are in contact with each other, and the second lens 2 is held in a state of being sandwiched between the first lens 1 and the holding recess 3a in the optical axis direction.

  As described above, since the first lens 1 and the second lens 2 are both formed of a plastic mold lens, a gate for molding is required.

  In the present embodiment, the gate at the time of molding the first lens 1 is disposed on the outer periphery of the first lens 1. Accordingly, the convex portion 1c (see FIG. 7), which becomes the remaining shape portion of the gate after molding, is provided on a part of the outer peripheral portion of the first lens 1 so as to protrude radially outward, and the inner peripheral portion of the fifth group lens holder 3 It is accommodated in a recess (not shown) formed in.

  On the other hand, the gate at the time of molding the second lens 2 is disposed on a cut surface of a D-cut shape in which a part of the outer peripheral portion of the second lens 2 is cut out flat. And the convex part 2a (refer FIG. 7) used as the remaining shape part of the gate of the 2nd lens 2 after shaping | molding is the inner peripheral surface of the fitting holding | maintenance part 1a of the 1st lens 1, and D cut surface of the 2nd lens 2. Is accommodated in a space formed between the two.

  An annular pressing member 4 is disposed on the front side of the first lens 1, and a pressing portion 4 b is provided on the back surface of the pressing member 4. The pressing portion 4 b presses the first lens 1 together with the second lens 2 toward the holding recess 3 a of the fifth group lens holder 3. As a result, the first lens 1 is positioned and fixed to the inner peripheral portion of the fifth group lens holder 3, and the second lens 2 is held by the holding recess 3 a via the first lens 1. Fixed to.

  A plurality of snap fits 4a projecting toward the back side are provided on the outer peripheral portion of the pressing member 4 at substantially equal intervals in the circumferential direction. The pressing member 4 is fixed to the fifth group lens holder 3 by hooking the plurality of snap fits 4 a to the plurality of latching protrusions 3 b provided corresponding to the fifth group lens holder 3.

  The pressing portion 4 b of the pressing member 4 is formed in a ring shape by an elastically deformable elastic material such as foamed material or rubber, and is located on the inner side in the radial direction from the outer peripheral portion of the pressing member 4. It is fixed to. As described above, the pressing portion 4b presses the first lens 1 together with the second lens 2 toward the holding recess 3a of the fifth group lens holder 3 to hold the lenses 1 and 2. At this time, by adjusting the elastic force of the pressing portion 4b, the lenses 1 and 2 are held without applying a large load to the lenses 1 and 2, in other words, without affecting the surface accuracy of the lenses. can do.

  FIG. 9 is a perspective view of the pressing member 4 as viewed from the back side. As shown in FIG. 9, the pressing portion 4 b is fixed to the outer peripheral side of the mask shape portion that limits the optical opening of the pressing member 4. In addition, you may form the press part 4b and a mask shape part integrally.

  On the outer peripheral side of the pressing portion 4b of the pressing member 4, a regulating surface 4d is formed along the circumferential direction. An annular recess is formed on the inner peripheral side of the restricting surface 4d of the pressing member 4, and the pressing portion 4b is positioned and fitted to the inner peripheral portion of the annular recess in a state protruding from the restricting surface 4d to the back side.

  Returning to FIG. 5, in the state where the first lens 1, the second lens 2, and the pressing member 4 are incorporated in the fifth group lens holder 3, the first lens 1 and the regulating surface 4 d of the pressing member 4 are A gap A is provided in the optical axis direction.

  In the state shown in FIG. 5, the first lens 1 and the second lens 2 are pressed together with the second lens 2 toward the holding recess 3a of the fifth group lens holder 3 by only the elastic repulsive force of the pressing portion 4b to hold the lenses 1 and 2. ing.

  Here, in the state shown in FIG. 5, when an external force such as an impact is applied to the fifth group lens holder 3, even if the first lens 1 is lifted in the optical axis direction, the first lens 1 is in contact with the regulating surface 4d. Further lifting is restricted. Thereby, damage of the 5th lens group holder 3 etc. can be prevented, and the outstanding impact resistance can be ensured.

  Further, as described above, the operation of fixing the pressing member 4 to the fifth group lens holder 3 is performed with the pressing member 4 pressing the first lens 1 toward the holding recess 3a.

  At this time, even if the first lens 1 is incorporated with an inclination with respect to the fifth group lens holder 3, the regulating surface 4 d abuts against the first lens 1 and pushes in the first lens 1. The tilt is corrected. That is, even if the first lens 1 is assembled with an inclination with respect to the fifth group lens holder 3, the first lens 1 is placed on a surface orthogonal to the optical axis by fixing the pressing member 4 to the fifth group lens holder 3. It can be returned to the normal position along.

  In addition, on the outer peripheral side of the regulating surface 4d of the pressing member 4, three protruding portions 4c protruding toward the back side are provided at substantially equal intervals in the circumferential direction, and the fifth group lens holder 3 corresponds to the protruding portion 4c. Three recesses 3c are provided at substantially equal intervals in the circumferential direction.

  When the pressing member 4 is fixed to the fifth group lens holder 3, the tip end portion of the protrusion 4 c abuts against the bottom surface of the recess 3 c in the optical axis direction, whereby the fifth group lens holder 3, the pressing member 4, and the like. The interval in the optical axis direction is regulated to a constant interval.

  Further, by arranging the protruding portion 4c on the outer peripheral side and in the vicinity of the regulating surface 4d, the position of the regulating surface 4d in the optical axis direction can be managed accurately, and the regulating surface 4d of the first lens 1 and the pressing member 4 can be managed. The dimension of the gap A in the optical axis direction can be kept constant.

  As described above, in the present embodiment, a plurality of lenses 1 and 2 can be held with high accuracy, and a lens holding structure with excellent impact resistance can be provided.

  The configuration of the present invention is not limited to that exemplified in the above embodiment, and the material, shape, dimensions, form, number, arrangement location, and the like can be changed as appropriate without departing from the scope of the present invention. It is.

  For example, in the above-described embodiment, the structure in which the first lens 1 and the second lens 2 are held with respect to the fifth group lens holder 3 is illustrated, but the structure in which only the first lens 1 is held with respect to the fifth group lens holder 3. It may be.

DESCRIPTION OF SYMBOLS 1 1st lens 1a Fitting holding | maintenance part 2 2nd lens 3 5 group lens holder 3c Recessed part 4 Pressing member 4b Pressing part 4c Protruding part 4d Restricting surface 16 Lens barrel 23 Digital camera

Claims (7)

A first lens;
A lens holder to which the back side of the first lens is fitted and fixed;
A pressing member provided on the front side of the first lens and fixed to the lens holder in a state where the first lens is pressed toward the lens holder;
In the pressing member,
An elastically deformable pressing portion that presses the first lens toward the lens holder when the pressing member is fixed to the lens holder;
A regulating surface that is disposed in the vicinity of the pressing portion with a gap in the optical axis direction between the first lens and that regulates lifting of the first lens in the optical axis direction. Characteristic lens unit.   The second lens is disposed on the back side of the first lens, is fitted in the optical axis direction with respect to the first lens, and has a second lens held on the lens holder on the back side. The lens unit described in 1.   A cylindrical fitting holding portion is provided on the back side of the first lens, and an outer peripheral portion of the second lens is fitted and held in the optical axis direction in the fitting holding portion. The lens unit according to claim 2.   The said regulation surface is arrange | positioned at the outer peripheral side of the said press part, The said press part is fitted by the recessed part formed in the inner peripheral side of the said control surface, The any one of Claim 1 thru | or 3 characterized by the above-mentioned. The lens unit according to claim 1.   5. The pressing member is provided with a protruding portion that protrudes toward the back side and abuts against the lens holder in the optical axis direction so as to be positioned on the outer peripheral side of the restricting surface. The lens unit according to any one of the above.   The lens unit according to claim 1, wherein the first lens is a plastic mold lens. An optical apparatus comprising the lens unit according to claim 1.