JP2006201690A - Lens frame positioning method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To rapidly perform the initial alignment of a lens frame without causing drastic eccentricity. <P>SOLUTION: Pins 76 and 77 for mounting a light shielding plate 46 on the mount surface 74 of a prism holding part are extended in an optical axis L1 direction. The lens frame 44 in which a 1st lens 18 is fixed is held in the recessed part 81 of a fixture 80, and the fixture 80 is pressed against the mount surface 74 of the prism holding part 45 so that the pin 77 may be fit in a hole 80b as soon as the pin 76 is inserted in a slot formed by notches 44a and 80a. Thus, the initial alignment of the lens frame 44 is performed, and the optical axis of the 1st lens 18 is nearly aligned with the optical axis L1 of a prism 35. After the lens frame 44 is temporarily fixed on the mount surface 74 of the prism holding part 45 by a leaf spring 82 in such a state, the fixture 80 is detached from the lens frame 44. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a lens frame positioning method that is used in an imaging apparatus such as a digital camera and performs initial positioning of a lens frame with respect to a lens barrel.

  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 has become widespread. 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). The lens frame that holds the lens arranged closest to the object side in the photographing optical system of this image pickup apparatus is temporarily fixed to the prism holding frame by two substantially U-shaped leaf springs, and is bonded after adjusting the eccentricity. It is fixed to the mounting surface with an agent.

On the other hand, when the first lens frame having the first optical system is assembled to the second lens frame having the second optical system, a jig is used to connect the first optical system and the second optical system. An optical axis adjustment method for performing optical axis alignment is disclosed (for example, Patent Document 2). Further, there is disclosed a lens center adjusting device capable of adjusting the centers of a plurality of lenses by rotating an eccentric shaft and moving a lens frame connected thereto in a direction perpendicular to the optical axis. (For example, patent document 3).
JP 9-2111287 A JP 2004-309818 A JP 2004-287279 A

  In the temporary fixing (initial positioning) of the lens frame in Patent Document 1 described above, there is a problem that a large amount of eccentricity occurs, and the subsequent eccentricity adjustment work becomes troublesome. The inventions described in Patent Documents 2 and 3 are all for performing optical axis alignment with high accuracy, and are not suitable for application to the initial positioning of the lens frame.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a lens frame positioning method capable of quickly performing initial positioning of a lens frame without causing significant eccentricity. .

  In order to achieve the above object, a lens frame positioning method according to the present invention is a lens that performs optical axis alignment between the optical axis of the lens and the optical axis of the lens barrel when the lens frame that holds the lens is attached to the lens barrel. In the frame positioning method, a projection is formed on the lens barrel and a hole is formed to fit the projection. A jig that holds the lens frame and presses it against the lens barrel is used, and the lens frame is held by the jig. After that, the optical axis alignment is performed by fitting the projection of the lens barrel into the hole of the jig and pressing the lens frame against the lens barrel. Further, the projection is provided between the lens frame and the lens barrel, and is also used for positioning a light shielding plate having an opening through which a light beam from the lens passes.

  A light-shielding plate having two mounting holes corresponding to the two protrusions and an opening through which a light beam from the lens is passed through a lens barrel having at least two protrusions long in the optical axis direction; After mounting by inserting a protrusion into the mounting hole, when mounting the lens frame holding the lens to the lens barrel with a light shielding plate in between, the optical axis of the lens and the optical axis of the lens barrel are aligned. In the lens frame positioning method to be performed, the projection is extended in the optical axis direction, and a hole is formed to fit the projection, and a jig that holds the lens frame and presses it against the lens barrel is used. After attaching the light-shielding plate to the lens barrel and inserting the hole of the jig into the protrusion protruding from the mounting hole of the light-shielding plate, and pressing the lens frame against the lens barrel with the jig, The optical axis is aligned. Further, the two mounting holes are disposed at positions opposite to each other across the opening of the light shielding plate, and the two protrusions are provided at positions corresponding to the two mounting holes. It is characterized by.

  In addition, the lens barrel incorporates a bending optical system that bends the light beam incident from the lens at a substantially right angle by a prism, and the lens frame is positioned with respect to the light incident side surface of the lens barrel holding the prism. It is characterized by being.

  According to the lens frame positioning method of the present invention, the projection is formed on the lens barrel, and the lens frame is held by the jig, and then the projection of the lens barrel is fitted into the hole of the jig to make the lens frame into the lens barrel. Since the optical axis is aligned by pressing, the initial position of the lens frame can be quickly determined without causing significant eccentricity. As a result, the time required for the eccentricity adjustment work performed thereafter can be shortened, and the total time required for lens positioning can be shortened. Further, since the projection formed on the lens barrel is also used for positioning the light shielding plate, the lens frame and the light shielding plate can be positioned with a simple configuration.

  Also, after extending the projection of the lens barrel to which the light-shielding plate is attached in the optical axis direction and holding the lens frame with a jig, press the lens frame against the lens barrel by fitting the projection of the lens barrel into the hole of the jig Since the optical axis is aligned with the lens, the initial positioning of the lens frame can be performed quickly without adding a new shape for positioning the lens frame, with a simple configuration, and without causing significant eccentricity. It can be carried out. As a result, the time required for the eccentricity adjustment work performed thereafter can be shortened, and the total time required for lens positioning can be shortened. The two mounting holes are arranged at positions opposite to each other across the opening of the light shielding plate, and the two protrusions are provided at positions corresponding to the mounting holes, so that the light shielding plate has a simple configuration. And the lens frame can be positioned.

  The lens barrel incorporates a bending optical system that bends the light beam incident from the lens substantially at right angles by a prism, and the lens frame is positioned with respect to the light incident side surface of the lens barrel holding the prism. It is preferable.

  1 and 2 showing the appearance of a digital camera that implements the lens frame positioning method of the present invention, the front surface of the digital camera 10 is provided with a stroboscopic light emitting unit 12 that irradiates the stroboscopic light at the center upper portion thereof. A photographing aperture 14 is provided on the side. The first lens 18 of the lens device 16 built in the digital camera 10 is exposed from the photographing aperture 14. A power button 20 and a release button 22 are provided on the upper surface. By pressing the release button 22, a still image for one frame is shot, and image data obtained by this shooting is recorded on a memory card (not shown) attached to the digital camera 10.

  As shown in FIG. 2, on the back of the digital camera 10, an LCD (liquid crystal display) 26, a zoom operation button 28 for zooming (zooming) the zoom type lens device 16 to the telephoto side and the wide angle side, and the digital camera 10 A cursor button 30 for performing various operations and settings is arranged. By operating the cursor button 30 and giving an instruction while looking at the menu displayed on the LCD 26, various settings such as switching between the shooting mode and the playback mode, and turning on / off the flash emission can be performed.

  Under the shooting mode, the LCD 26 displays the subject image being shot as a through image of a moving image, and the user can know the shooting range by observing the through image. In the playback mode, an image recorded on the memory card can be selected and displayed on the LCD 26.

  As shown in FIGS. 3 and 4, the lens device 16 is a bending optical system using a prism. By using this bending optical system, the thickness of the digital camera 10 is reduced. The lens device 16 includes an upper unit 31, a lower unit 32, and a shutter unit 33 assembled between these units 31, 32, and these are integrally assembled by screws or the like.

  The upper unit 31 includes an upper lens barrel 34, a first lens group G1, a prism 35, a second lens group G2 to a fourth lens group G4, a zoom motor 36, and the like assembled on the upper lens barrel 34. The upper barrel 34 constitutes the barrel of the lens device 16 together with the lower barrel 40 of the lower unit 32. Note that the first lens group G1 is composed of one first lens 18 in the present embodiment, and will be referred to as the first lens 18 hereinafter. The first lens group G1 may be composed of a plurality of lenses.

  The first lens 18 arranged closest to the object side is attached to the front surface of the prism holding portion 45 provided on the upper part of the upper barrel 34 while being held by the lens frame 44, and is exposed to the outside from the photographing opening 14. Is done. On the back surface of the first lens 18, a light shielding plate 46 for shielding light unrelated to photographing is disposed.

  The prism holding unit 45 is assembled with a prism 35 in which the light incident surface 35a and the light emitting surface 35b are orthogonal to each other, and the prism 35 faces the first lens 18 with the light incident surface 35a sandwiching the light shielding plate 46 therebetween. It is arranged. The prism 35 bends subject light (light beam of the optical axis L1) incident on the light incident surface 35a from the first lens 18 by 90 degrees and emits the light as a light beam of the optical axis L2 from the light emitting surface 35b.

  The second lens group G2 includes two lenses 48 and 49, is held by the lens holder 50, and is fixed immediately below the light exit surface 35b of the prism 35. The third lens group G3 includes three lenses 52 to 54, which are held by a lens holder 55. The lens holder 55 is moved along the optical axis L2 of the lens device 16 by the zoom motor 36, and zooming is performed. The fourth lens group G4 includes a single lens 58. The lens 58 is held by a lens holder 59 and fixed to the lower part of the upper barrel 34.

  The lower unit 32 includes a lower lens barrel 40, a fifth lens group G5 assembled to the lower lens barrel 40, a focus adjusting motor (not shown), and the like. The fifth lens group G5 includes three lenses 62 to 64, and each lens 62 to 64 is held by a lens holder 65. The lens holder 65 is moved up and down along the optical axis L2 of the lens device 16 by a focus adjustment motor, and focus adjustment is performed.

  A CCD image sensor 66 is assembled in the lower opening of the lower barrel 40, and a subject image is formed on the light receiving surface by the first lens 18 to the fifth lens group G5 configured as described above. A low-pass filter 68 is disposed between the CCD image sensor 66 and the fifth lens group G5 in order to prevent the occurrence of moiré and false colors.

  In FIG. 5 showing a state in which the lens frame 44 holding the first lens 18 is positioned on the front surface of the prism holding portion 45 of the upper barrel 34 via the light shielding plate 46, the first lens 18 is, for example, the back surface of the lens frame 44. From the side, it is inserted into the lens frame 44 and then fixed by adhesion. The light shielding plate 46 is a thin plate-like member having a predetermined thickness, and includes a substantially circular mask portion 70 and projecting pieces 71 a to 71 d provided around the mask portion 70.

  The mask portion 70 is slightly smaller than the inner diameter of the lens frame 44 so as to substantially cover the back surface of the first lens 18, and a substantially rectangular opening 70a through which only a light beam effective for photographing is passed is formed at the center. It is. The mask unit 70 prevents light unrelated to photographing from entering the prism 35 from the first lens 18. The protruding pieces 71a to 71d are provided at positions corresponding to the respective corners of the opening 70a, and a pair of protruding pieces 71a and 71c provided so as to sandwich the center of the opening 70a are provided with mounting holes 72, respectively. .

  The front surface of the prism holding portion 45 is provided with an opening that exposes the light incident surface 35 a of the prism 35, and the periphery thereof is an attachment surface 74 of the lens frame 44. The attachment surface 74 is a plane perpendicular to the optical axis L1. On the attachment surface 74, two pins 76 and 77 that project through the attachment holes 72 of the light shielding plate 46 and attach the light shielding plate 46 to the front surface of the prism holding portion 45 are projected. The pins 76 and 77 are extended longer in the direction of the optical axis L1 than the length necessary for attaching the light shielding plate 46, and are also used for initial positioning of the lens frame 44. Note that an arc-shaped notch 44 a with which one pin 76 abuts is formed on a part of the outer periphery of the lens frame 44.

  The light shielding plate 46 is assembled to the front surface of the prism holding portion 45 by inserting the pins 76 and 77 corresponding to the mounting holes 72, respectively. The outer diameters of the pins 76 and 77 are the same as the inner diameter of the mounting hole 72. By fitting the pins 76 and 77 into the mounting hole 72, the center of the opening 70a of the light shielding plate 46 is aligned with the optical axis L1 of the prism 35. The light shielding plate 46 is positioned so as to match. The light shielding plate 46 is fixed to the front surface of the prism holding portion 45 by dropping an adhesive at the position of each mounting hole 72.

  A jig 80 is used to attach the lens frame 44 to the front surface of the prism holder 45. The jig 80 has a bowl shape, and the shape of the inner wall constituting the recess 81 is an arc shape so as to abut against and hold the outer peripheral surface of the lens frame 44 as shown in FIG. It comprises a pair of arcuate surfaces 81a and a pair of flat surfaces 81b. An attachment space 84 is provided so as not to obstruct the two leaf springs 82 to be described later.

  The jig 80 is formed with a notch 80a into which the pin 76 is inserted and a hole 80b into which the pin 77 is fitted substantially at diagonal positions. Further, the notch 80 a is connected to one arcuate surface 81 a and has a long hole shape extending in the radial direction from the center of the jig 80. Accordingly, when the lens frame 44 is held in the concave portion 81 of the jig 80, an elongated hole for easily inserting the pin 76 is formed by the notch 44a and the notch 80a.

  When the lens frame 44 is held in the concave portion 81 of the jig 80, the pins 76 and 77 are inserted into the notches 80a and the holes 80b, respectively, and pressed against the mounting surface 74 of the prism holding portion 45. The frame 44 is held by the jig 80, and the jig 80 is positioned with respect to the mounting surface 74 of the prism holding portion 45. As a result, the positioning of the lens frame 44 with respect to the mounting surface 74 of the prism holding portion 45, that is, the initial positioning of the lens frame 44 is performed.

  In this state, the lens frame 44 is temporarily fixed by two substantially U-shaped plate springs 82, adjusted for eccentricity, and then fixed to the mounting surface 74 with an adhesive. One end of each leaf spring 82 is applied to the prism holding portion 45 on the back surface, and the other end is applied to the pressed portion 44 b of the lens frame 44, so that the lens frame 44 is pressed against the mounting surface 74. In addition, the code | symbol 80c shown in FIG. 5 is a notch for making attachment work of the leaf | plate spring 82 easy.

  Next, the operation of the above configuration will be described. First, the pin 76 is inserted into the mounting hole 72 of the light shielding plate 46 so that the light shielding plate 46 is positioned on the mounting surface 74 of the prism holding portion 45 and then fixed with an adhesive. Next, the lens frame 44 to which the first lens 18 is fixed is held in the concave portion 81 of the jig 80, and at the same time the pin 76 is inserted into the long hole by the notches 44a and 80a, the pin 77 is fitted into the hole 80b. As described above, the jig 80 is pressed against the mounting surface 74 of the prism holding portion 45.

  Since the lens frame 44 is held by the jig 80 and the jig 80 is positioned on the mounting surface 74 of the prism holding unit 45, the lens frame 44 is positioned with respect to the mounting surface 74 of the prism holding unit 45. As a result, the optical axis of the first lens 18 and the optical axis L1 of the prism 35 substantially coincide with each other, and an initial position is determined as positioning when the lens frame 44 is assembled. In this state, the lens frame 44 is temporarily fixed to the mounting surface 74 of the prism holding portion 45 by the leaf spring 82. Thereafter, when the jig 80 is pulled straight in the direction of the optical axis L so as to be separated from the prism holding portion 45, the jig 80 is removed from the lens frame 44.

  The upper unit 31 is assembled with a lower unit 32 and a shutter unit 33, which are assembled and assembled with various components, before the lens frame 44 is mounted, and the lens device 16 is assembled with the lens frame 44 temporarily fixed. Is almost complete.

  After the lens frame 44 is temporarily fixed, the lens device 16 is sent to an eccentricity adjustment process. In the eccentricity adjustment step, for example, a predetermined test chart is photographed by the CCD image sensor 66 through the lens device 16 to be adjusted, and is orthogonal to the optical axis of the first lens 18 while observing the image being photographed. By moving the lens frame 44 on the surface to be moved, the first lens 18 is moved to determine the position where the best image is obtained. At this time, since the optical position of the first lens 18 and the optical axis L1 are already substantially aligned by the initial positioning of the lens frame 44, the work of determining the position where the best image can be obtained is extremely short. Can finish in time.

  When the position where the best image can be obtained is determined, the adhesive is dropped onto, for example, the notch 44a with which the pin 76 is in contact with the position, and the lens frame 44 is bonded and fixed to the upper unit 31. In addition, the fixing method of the 1st lens 18, the lens frame 44, and the light-shielding plate 46 is not limited to the adhesive fixing using an adhesive agent, You may use various fixing methods. Further, the leaf spring 82 remains attached after the lens device 16 is completed.

  The lens device 16 is completed as described above. The completed lens device 16 is sent to the manufacturing process of the digital camera 10 and assembled inside the digital camera 10. Then, the first lens 18 is exposed from the photographing opening 14.

  In the above embodiment, the optical path of the lens apparatus is bent using the prism, but the optical path may be bent using another member, for example, a mirror. Further, the present invention can be used even if the optical path is not a bent optical system. Furthermore, although the opening of the light shielding plate is substantially rectangular, it goes without saying that the present invention can be used in various shapes such as a circle.

  Further, although the case where the present invention is applied to a digital camera has been described in the present embodiment, the present invention is not limited to the application to a digital camera, and various optical apparatuses such as a camera and a projector using a silver salt film are used. It can be applied to a lens apparatus.

It is a perspective view which shows the front side of the digital camera which implemented this invention. It is a perspective view which shows the back side of a digital camera. It is a perspective view which shows the external appearance of a lens apparatus. It is sectional drawing which shows the structure of a lens-barrel. It is a disassembled perspective view which shows a mode that a lens frame and a light-shielding plate are attached to an upper lens barrel. It is sectional drawing of the jig | tool which shows the relationship between a lens frame and a jig | tool.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Digital camera 16 Lens apparatus 18 1st lens 34 Upper lens barrel 35 Prism 44 Lens frame 44a, 80a Notch 45 Prism holding part 46 Light-shielding plate 74 Mounting surface 76, 77 Pin 80 Jig 80b Hole 82 Leaf spring

Claims (5)

In the lens frame positioning method for aligning the optical axis of the lens and the optical axis of the lens barrel when attaching the lens frame holding the lens to the lens barrel,
While forming a protrusion on the lens barrel,
A hole that fits with the protrusion is formed, and using a jig that holds the lens frame and presses it against the lens barrel,
After the lens frame is held by the jig, the optical axis alignment is performed by fitting the projection of the lens barrel into the hole of the jig and pressing the lens frame against the lens barrel. Method.   2. The lens frame positioning according to claim 1, wherein the protrusion is provided between the lens frame and the lens barrel and is also used for positioning a light shielding plate having an opening through which a light beam from the lens passes. Method. A light-shielding plate in which two mounting holes corresponding to the two protrusions and an opening through which a light beam from the lens passes is formed in a lens barrel having at least two protrusions long in the optical axis direction. A lens that performs optical axis alignment between the optical axis of the lens and the optical axis of the lens barrel when the lens frame that holds the lens is attached to the lens barrel with a light-shielding plate sandwiched between the lens frame and the lens barrel. In the frame positioning method,
While extending the protrusion in the optical axis direction,
A hole that fits with the protrusion is formed, and using a jig that holds the lens frame and presses it against the lens barrel,
After the projection is inserted into the mounting hole and the light shielding plate is attached to the lens barrel, a jig hole is fitted into the projection protruding from the mounting hole of the light shielding plate, and the lens frame is attached to the lens barrel with the jig. A lens frame positioning method, wherein the optical axis alignment is performed by pressing.   The two mounting holes are disposed at positions opposite to each other across the opening of the light shielding plate, and the two protrusions are provided at positions corresponding to the two mounting holes. The lens frame positioning method according to claim 3. The lens barrel incorporates a bending optical system that bends the light beam incident from the lens substantially at right angles by a prism, and the lens frame is positioned with respect to a light incident side surface of the lens barrel holding the prism. The lens frame positioning method according to any one of claims 1 to 4, wherein the lens frame positioning method is provided.

Images