JP2006189649A - Lens positioning method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens positioning method by which a lens is accurately positioned in spite of simple constitution and which contributes to the thinning of an imaging apparatus such as a digital camera. <P>SOLUTION: A lens frame 44 is pressed in from the back of a 1st lens 26 so that the front 26b side of the 1st lens 26 may project forward in an optical axis L1 direction from the front end 44b of the lens frame 44, and the 1st lens 26 and the lens frame 44 which are integrated are put inside a 1st tool 50. Next, the rear end 44d of the lens frame 44 projecting from the 1st tool is pressed by a 2nd tool 52. When the lens frame 44 is moved to the 1st tool side to a position obtained just before the front end 44b of the lens frame 44 projects more forward than the front 26b of the 1st lens 26, a 2nd pressing surface 52b abuts on the rear end face 26c of the 1st lens 26 projecting from the rear end 44d of the lens frame 44 so as to stop the movement of the 2nd tool. Thus, the positioning of the 1st lens 26 in an optical axis L1 direction in the lens frame 44 is accurately performed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a lens positioning method that is used in an imaging apparatus such as a digital camera and determines the position of a lens in the optical axis direction with respect to a lens frame.

  A digital camera that photoelectrically converts an optical image using a solid-state imaging device such as a CCD and stores digital image data in a storage device such as a memory card is commercially available. Many of such digital cameras are equipped with an optical zoom lens as a photographing lens. This optical zoom lens is more advantageous in terms of image quality than digital zoom, which performs zooming by processing image signals, but the lens on the objective side protrudes greatly from the front of the camera body as zooming occurs, so when shooting, There are many requests for improvement in terms of usability and appearance.

Therefore, by using a prism as a part of the photographic optical system, the optical axis is bent, and the zoom lens is moved in the apparatus and in a direction parallel to the front surface of the apparatus, so that the objective lens is moved to the front surface of the apparatus. There is known an imaging apparatus that does not protrude from the camera (for example, Patent Document 1).
JP 9-2111287 A

  The imaging device described in Patent Document 1 is thinner than the conventional one by the bending optical system using the prism. However, recent digital cameras tend to be thinner. By the way, since the lens frame of the objective lens is provided with a lens positioning protrusion that extends to the front surface of the lens, it is difficult to reduce the thickness of the lens barrel in which the objective lens is incorporated in the optical axis direction. . Thus, although it is conceivable to omit this protrusion, there arises a problem that the objective lens cannot be positioned in the optical axis direction.

  The present invention has been made in view of the above circumstances, and provides a lens positioning method capable of accurately positioning a lens with a simple configuration and contributing to thinning of an imaging apparatus such as a digital camera. There is to do.

  In order to achieve the above object, a lens positioning method according to the present invention includes a lens positioning method for determining a position in the optical axis direction of a lens with respect to a lens frame that abuts a side surface of the lens and holds the lens. A first jig for holding the lens and the lens frame in a state where at least a part of the lens frame is in contact with the second jig for pressing the lens frame from the rear end side, and an optical axis from the front end of the lens frame. The lens and the lens frame are held by the first jig with the front surface of the lens protruding forward in the direction, and then the lens frame is pressed by the second jig forward from the rear end side in the optical axis direction. The optical axis direction of the lens with respect to the lens frame is moved relative to the lens and the pressing of the second jig to the lens frame is stopped immediately before the front end of the lens frame projects forward from the front surface of the lens. Position and wherein the determining the.

  The second jig includes a first contact surface that is in contact with a rear end surface of the lens frame, and a second contact surface that is different in height in the optical axis direction from the first contact surface. The first abutment surface is brought into contact with the rear end surface of the lens frame and pressed forward in the optical axis direction, and the lens frame is moved to a position just before the front end of the lens frame projects forward from the front surface of the lens. The second abutment surface abuts on at least a part of the rear end surface of the lens when the lens frame is moved relative to the lens, thereby preventing further movement of the lens frame by the second jig.

  According to the lens positioning method of the present invention, the lens and the lens frame are held by the first jig with the front surface of the lens projecting forward from the front end of the lens frame in the optical axis direction, and then the lens frame by the second jig. The lens frame is moved relative to the lens by pressing the lens frame forward from the rear end side, and the lens frame is moved to the lens frame by the second jig immediately before the front end of the lens frame protrudes forward from the front surface of the lens. Since the position in the optical axis direction of the lens with respect to the lens frame is determined by stopping the pressing, the lens can be accurately positioned with a simple configuration, which contributes to a reduction in the thickness of an imaging apparatus such as a digital camera.

  The second jig includes a first contact surface that is in contact with the rear end surface of the lens frame, and a second contact surface that is different in height in the optical axis direction from the first contact surface. The first abutment surface is brought into contact with the rear end surface of the lens frame and pressed forward in the optical axis direction, and the lens frame is moved relative to the lens to a position immediately before the front end of the lens frame projects forward from the front surface of the lens. When the lens is moved, it is preferable that the second abutting surface abuts at least a part of the rear end surface of the lens to prevent further movement of the lens frame by the second jig.

  1 and 2, the digital camera 10 includes a strobe light emitting unit 12, a release button 14, a power switch 15, a zoom operation button 18 that changes a zoom lens 16 that is a photographing lens to a telephoto side and a wide side, a digital camera, There are provided a cross operation button 20 for performing various operations and settings, and a liquid crystal panel 22 for displaying a real-time image, a reproduced image, and the like during framing and shooting. In addition, a lens barrel 24 according to the present invention of the zoom lens 16 is provided inside the digital camera 10. Reference numeral 26 denotes a first lens provided in the lens barrel 24.

In FIG. 3 showing the appearance of the lens barrel 24, the lens barrel 24 is composed of an upper barrel 30 and a lower barrel 31, and a shutter is provided between the upper barrel 30 and the lower barrel 31. A shutter unit 32 having a device and a drive mechanism for driving the shutter device is sandwiched.

  In FIG. 4 showing the internal structure of the lens barrel 24, the lens barrel 24 includes a first lens group G1, a prism 34, a second lens group G2, a third lens group G3, and a fourth lens group G4. An optical system is provided. These lenses and prisms are held by the frames 36 to 40 and the like.

  The frame 36 holds the first lens group G1 including the first lens 26 and the second and third lenses 42 and 43 and the prism 34. The first lens 26 is positioned and fixed to the lens frame 44, and the lens frame 44 is assembled to the frame 36 by a pair of pressers 46 and 47 (see FIG. 3), whereby the first lens 26 is fixed to the prism 34. Fixed.

  A method of positioning the first lens 26 on the lens frame 44 will be described with reference to FIG. The inner diameter of the opening 44a of the lens frame 44 exactly matches the outer diameter of the first lens 26, and when the lens frame 44 is pushed in from the back of the first lens 26, the side surface 26a of the first lens 26 becomes the opening 44a. The first lens 26 is fitted into the lens frame 44 without slacking in contact with the inner wall surface ((A) → (B)). At this time, the front surface 26b side of the first lens 26 is in a state of protruding forward from the front end 44b of the lens frame 44 in the optical axis L1 direction (B).

  The integrated first lens 26 and lens frame 44 are placed inside the first jig 50 having a bowl shape with the first lens 26 in front (downward in the drawing). An opening 50a is formed in the bottom plate of the first jig 50, and the front surface 26b of the first lens 26 is in contact with the edge, and the outer peripheral surface 44c of the lens frame 44 is inward of the side of the first jig. It abuts against the wall surface 50b (C).

  Next, the rear end 44 d of the lens frame 44 protruding from the first jig is pressed by the second jig 52. The pressing surface of the second jig 52 is abutted against the first pressing surface 52a that presses the rear end 44d of the lens frame 44 and the rear end surface 26c of the first lens 26. The second pressing surface 52b.

  As the rear end 44d of the lens frame 44 is pushed by the first pressing surface 52a, the lens frame 44 is moved relative to the first lens 26 and pushed into the back side of the first jig 50. The lens frame 44 reaches a position immediately before the front end 44b of the lens frame 44 protrudes forward from the front surface 26b of the first lens 26, that is, a position before the front end 44b of the lens frame 44 contacts the bottom surface of the first jig 50. When moved to the first jig 50 side, the second pressing surface 52b comes into contact with the rear end face 26c of the first lens 26 protruding from the rear end 44d of the lens frame 44, and the movement of the second jig is prevented (D ). Thereby, the positioning of the first lens 26 in the optical axis L1 direction with respect to the lens frame 44 is accurately performed.

  Thereafter, the first lens 26 and the lens frame 44 are taken out from the jigs 50 and 52. Since the first lens 26 and the lens frame 44 are fitted without slack, their relative positions will not be shifted under normal handling, but they are fixed before being incorporated into the frame 36. For this fixing, for example, a photo-curing resin is used. Since the inner diameter on the rear end 44 d side of the lens frame 44 is set larger than the outer diameter of the first lens 26, a space 54 is provided between the rear end 44 d side of the lens frame 44 and the side surface 26 a of the first lens 26. Is formed. When the light curable resin 56 is poured and then light is applied, the light curable resin 56 is cured and the first lens 26 is fixed to the lens frame 44 (see FIG. 6).

  After the lens frame 44 to which the first lens 26 is fixed in this way is brought into contact with the front portion of the frame 36, as shown in FIG. 6, a pair of elastic pressing members 46 and 47 (see FIG. 3) are used. Fix to the frame 36. The presser 47 is bent in a U shape, one end 47a is screwed to the back side of the frame 36, and the other end 47b is engaged with the edge portion 44e of the lens frame 44, so that the lens frame 44 is pressed against the frame 36. The pressing tool 46 having the same configuration as that of the pressing tool 47 is provided at a substantially pointed position with respect to the center of the first lens 26, and presses the lens frame 44 against the frame 36 in cooperation with the pressing tool 47. .

  As shown in FIG. 4, the optical axis L1 of the first lens 26 is perpendicular to the optical axis L2 of the second and third lenses 51 and 52, and the prism 34 is incident from the first lens 26 along the optical axis L1. The reflected light beam is reflected toward the second lens 51. In addition, a light blocking aperture 58 is provided between the first lens 26 and the frame 36. In the second and third lenses 42 and 43, various aberrations that occur when the light beam from the first lens 26 is reflected by the prism 34 are corrected.

  On the image plane side of the third lens 43, a frame 37 holding the second lens group G2 including the fourth, fifth, and sixth lenses 60, 61, and 62 is disposed so as to be movable in the direction of the optical axis L2. The fourth to sixth lenses 60 to 62 move during zooming. A frame 38 holding the third lens group G3 including the seventh lens 63 is disposed on the image plane side of the frame 37, and a shutter device 64 having a diaphragm function is disposed on the image plane side.

  A frame 40 is disposed on the image plane side of the shutter device 64, and a frame 39 holding a fourth lens group G <b> 4 including eighth, ninth, and tenth lenses 66, 67, 68 is disposed inside the frame 40. It is incorporated so as to be movable in the direction of the optical axis L2. A diaphragm plate 69 is disposed on the image plane side of the tenth lens 63 in order to suppress the occurrence of ghosts and the like, and a low-pass filter 70 and a CCD image sensor 72 for cutting off extra color components are further fixed on the image plane side. Has been.

  The frame 37 is moved during zooming, and the frame 39 is controlled by a controller (not shown) so as to move during zooming and focusing. For example, the frame 37 and the frame 39 are interlocked during zooming. In zooming to the wide angle side, the second lens group G2 moves to the prism 34 side and the fourth lens group G4 moves to the CCD image sensor 72 side, and in zooming to the telephoto side, the second lens group G2 and the fourth lens group G4 are moved to the prism 34 side. The lens group G4 moves to the third lens group G3 side.

  The operation of the above configuration will be described. As shown in FIG. 5, the lens frame 44 is pushed in from the rear of the first lens 26 so that the front surface 26b side of the first lens 26 protrudes forward from the front end 44b of the lens frame 44 in the optical axis L1 direction. The first lens 26 and the lens frame 44 are placed inside the first jig 50. Next, the rear end 44 d of the lens frame 44 protruding from the first jig is pressed by the second jig 52.

  When the lens frame 44 moves to the first jig 50 side to a position immediately before the front end 44b of the lens frame 44 projects forward from the front surface 26b of the first lens 26, the first projecting from the rear end 44d of the lens frame 44. The second pressing surface 52b comes into contact with the rear end surface 26c of the lens 26, and further movement of the second jig is prevented. Thereby, the positioning of the first lens 26 in the optical axis L1 direction with respect to the lens frame 44 is accurately performed.

  The jigs 50 and 52 are removed from the first lens 26 and the lens frame 44, and the photo-curing resin 56 is poured into a space 54 formed between the rear end 44 d side of the lens frame 44 and the side surface 26 a of the first lens 26. , Hit the light. As shown in FIG. 6, the photo-curing resin 56 is cured and the first lens 26 is fixed to the lens frame 44. In this way, since the lens can be accurately positioned on the lens frame without providing a lens positioning protrusion that goes around the lens front surface, the optical axis direction of the photographing optical system (in this embodiment, the optical axis L1 direction). ) Can be reduced. Therefore, the thickness of the digital camera 10 using the lens barrel 24 can be reduced.

  Note that the adhesive for fixing the lens to the lens frame is not limited to the photo-curing resin, and may be, for example, an epoxy resin.

  In the embodiment described above, the lens barrel 24 provided with an optical system including 10 lenses in 4 groups and one prism is illustrated, but the number of lenses and the number of lens groups are not limited to this. For example, a 4-group 9-sheet configuration or a 5-group 11-sheet configuration may be used. Moreover, although CCD was used as an image pick-up element, you may use CMOS, for example.

  In the above embodiment, the present invention is applied to an optical system of a digital camera. However, the present invention is not limited to this, and for example, a camera-equipped mobile phone, a portable information terminal (PDA), a silver It can also be applied to an optical system of a salt camera, and further, an optical device such as a projector that synthesizes image light from a plurality of primary color lights and projects it onto a screen, or an optical device such as an optical pickup device such as a DVD, CD-ROM, MD It can also be applied to systems.

It is a perspective view which shows the external appearance of a digital camera from the front side. It is a perspective view which shows the external appearance of a digital camera from the back side. It is a perspective view which shows the external appearance of a lens-barrel. It is sectional drawing which cut | disconnected the lens barrel in the surface containing the optical axis L1 and the optical axis L2. It is explanatory drawing which shows the process of positioning a 1st lens to a lens frame. It is sectional drawing which shows a mode that the lens frame to which the lens was adhere | attached and fixed was attached to the flame | frame.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Digital camera 16 Zoom lens 24 Lens barrel 26 1st lens 44 Lens frame 50 1st jig | tool 52 2nd jig | tool 56 Photocurable resin

Claims (2)

In the lens positioning method for determining the position of the lens in the optical axis direction with respect to the lens frame that contacts the side surface of the lens and holds the lens,
Using a first jig for holding the lens and the lens frame in a state where at least a part of the front surface of the lens is in contact, and a second jig for pressing the lens frame from the rear end side,
The lens and the lens frame are held by the first jig with the front surface of the lens projecting forward in the optical axis direction from the front end of the lens frame, and then the lens frame is moved forward in the optical axis direction from the rear end side by the second jig. The lens frame is moved relative to the lens by pressing the lens frame, and the pressing to the lens frame by the second jig is stopped immediately before the front end of the lens frame projects forward from the front surface of the lens. A lens positioning method characterized by determining a position of a lens in an optical axis direction with respect to a lens frame. The second jig includes a first contact surface that is in contact with a rear end surface of the lens frame, and a second contact surface having a height different from that of the first contact surface in the optical axis direction. The first abutment surface is brought into contact with the rear end surface of the lens frame and pressed forward in the optical axis direction, and the lens frame is positioned relative to the lens until just before the front end of the lens frame protrudes forward from the front surface of the lens. The second abutment surface abuts on at least a part of the rear end surface of the lens when the lens frame is moved, thereby preventing further movement of the lens frame by the second jig. The lens positioning method as described.

Images