JP2007256703A - Adjustment method, lens barrel manufactured using the adjustment method, and camera having the lens barrel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To facilitate the adjustment of an optical axis. <P>SOLUTION: First, lens holding frames 60 and 70 are disposed in lens holders 30 and 40 each accommodated in a lens barrel 10. Next, piezoelectric elements 80A and 80B are disposed around the lens holding frames 60 and 70 respectively. After all optical members including the lens holders 30 and 40 are accommodated in the lens barrel 10, the piezoelectric elements 80A and 80B are driven to adjust the positions of the lens holding frames 60 and 70. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an adjustment method, a lens barrel manufactured using the adjustment method, and a camera including the lens barrel.

In an interchangeable lens for a camera, it is necessary to adjust the optical axis in order to obtain predetermined optical performance based on design specifications. The relative positional shift of the plurality of optical elements constituting the interchangeable lens is adjusted by moving the optical element or the optical unit (a group of the plurality of optical elements) in a direction perpendicular to the optical axis. The optical axis is adjusted while an optical measuring instrument is attached to the mount of the interchangeable lens and the optical performance is confirmed on the monitor of the optical measuring instrument.
JP 7-72366 A

  However, since a zoom ring, a focus ring, etc. are arranged around the interchangeable lens inside the lens barrel with the optical axis as the center, an optical element such as a lens is mounted with the optical measuring instrument attached to the mount portion of the interchangeable lens. It is difficult to adjust the optical axis by moving the lens from the outside. If an optical axis shift is detected, remove the optical measuring instrument from the interchangeable lens mount, move the optical element in the specified direction, and then attach the optical measuring instrument to the interchangeable lens mount again. Confirm. The optical axis is adjusted by repeating this operation. Therefore, the adjustment of the optical axis of the interchangeable lens is troublesome and complicated.

  The present invention has been made in view of such circumstances, and the subject thereof is an adjustment method capable of easily adjusting the optical axis, a lens barrel manufactured using the adjustment method, and the lens barrel. Is to provide a camera.

  In order to solve the above-mentioned problem, an invention according to claim 1 is given to a first step of arranging an optical member on a lens holder accommodated in a lens barrel, and after the first step, around the optical member. A second step of disposing a displacement element that moves the optical member based on the physical quantity, and a third step of adjusting the position of the optical member by driving the displacement element after the second step. It is characterized by being.

  According to a second aspect of the present invention, in the adjustment method according to the first aspect, the moving direction of the optical member is a direction orthogonal to the optical axis of the lens barrel.

  According to a third aspect of the present invention, in the adjustment method according to the first or second aspect, before the third step, another optical member is accommodated in the lens barrel.

  According to a fourth aspect of the present invention, in the adjustment method according to any one of the first to third aspects, the optical member is fixed to the lens holder using an adhesive after the third step. To do.

  The invention according to claim 5 is manufactured by using the adjustment method according to any one of claims 1 to 4.

  According to a sixth aspect of the present invention, there is provided a camera comprising the lens barrel according to the fifth aspect.

  According to the present invention, the optical axis can be easily adjusted.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1A is a conceptual diagram illustrating a cross section of an interchangeable lens according to an embodiment of the present invention before optical axis adjustment, and FIG. 1B is a conceptual diagram illustrating a cross section taken along line 1b-1b of FIG. FIG. 2A is a conceptual diagram showing a cross section of the interchangeable lens according to an embodiment of the present invention after adjusting the optical axis, and FIG. 2B is a cross section taken along line 2b-2b of FIG. FIG.

  This interchangeable lens includes a focus ring 15, lens holders 20, 30, 40, 50, lens holding frames 60, 70, a cam ring 35, a fixed cylinder 45, piezoelectric elements (displacement elements) 80A, 80B, and a drive device 90. ing.

  The focus ring 15 holds the first lens holder 20 and the second lens holder 30.

  The first lens holder 20 holds lenses 20a and 20b.

  A lens holding frame 60 is accommodated in the second lens holder 30. Lenses 60 a and 60 b are held on the lens holding frame 60. A protrusion 61 is provided on the outer peripheral surface of the second lens holder 30. The protrusion 61 is engaged with a cam groove 26 provided on the inner peripheral surface of the focus ring 15. The rotation of the second lens holder 30 around the optical axis is restricted by the guide member 5. The lens holding frame 60 and the lenses 60a and 60b constitute an optical member.

  The lens holding frame 60 is held by the second lens holder 30 by a pressing member 65 having an elastic member 65a.

  Four piezoelectric elements 80A are arranged on the inner peripheral surface of the second lens holder 30 (the piezoelectric element 80A and the outer peripheral surface of the lens holding frame 60 are opposed to each other with a gap of 10 and several μm). The four piezoelectric elements 80A are arranged at an interval of 90 °. The piezoelectric element 80 </ b> A is connected to a driving device 90 provided outside the lens barrel 10 via a power supply line 91. When the voltage applied to the piezoelectric element 80A changes, the length of the piezoelectric element 80A (the radial length of the second lens holder 30) changes.

  A fixed cylinder 45 is fitted to the cam ring 35 via a cam groove and a pin (not shown). The guide portion 5 is fixed to the fixed cylinder 45. The third lens holder 40 and the fourth lens holder 50 are fitted to the guide portion 5 via cam grooves and pins (not shown). The rotation of the third lens holder 40 and the fourth lens holder 50 around the optical axis is restricted by the guide member 5.

  A lens holding frame 70 is accommodated in the third lens holder 40. The lens holding frame 70 holds lenses 70a and 70b. The lens holding frame 70 and the lenses 70a and 70b constitute an optical member. The lens holding frame 70 is held by the third lens holder 40 by a pressing member 75 having an elastic member 75a.

  Four piezoelectric elements 80B are arranged on the inner peripheral surface of the third lens holder 40 (the piezoelectric element 80B and the outer peripheral surface of the lens holding frame 60 are opposed to each other with a gap of 10 and several μm). The four piezoelectric elements 80B are arranged with an interval of 90 ° (see FIG. 1B). A driving device 90 provided outside the lens barrel 10 is connected to the piezoelectric element 80B via a power supply line 91. When the voltage applied to the piezoelectric element 80B changes, the length of the piezoelectric element 80B (third lens holder) 40 radial length).

  The fourth lens holder 50 holds lenses 50a and 50b.

  A zoom ring 11 is mounted on the outer peripheral surface of the focus ring 15 and the outer peripheral surface of the cam ring 35. Zooming is performed by rotating the zoom ring 11 around the optical axis L, and focusing is performed by rotating the focus ring 15 around the optical axis L.

  The lens barrel 10 is provided with a mount portion 12 to be attached to a lens mounting portion (not shown) on the camera body side. An optical measuring instrument (not shown) provided with a monitor for adjusting the optical axis is mounted on the mount portion 12.

  Next, the operation of this interchangeable lens will be described.

  For zooming, the zoom ring 11 is rotated around the optical axis L.

  When the zoom ring 11 is turned to the telephoto side, the cam ring 35 rotates around the optical axis L integrally with the zoom ring 11. When the cam ring 35 rotates about the optical axis L, the third lens holder 40 and the fourth lens holder 50 move to the left, and the focus ring 15, the first lens holder 20, and the second lens holder 30 are shown in FIG. Move to the left of 2.

  When the zoom ring 11 is turned to the wide side, the third lens holder 40 and the fourth lens holder 50 move in the right direction, and the focus ring 15, the first lens holder 20, and the second lens holder 30 move in the right direction. Moving.

  Further, in order to perform focusing, the focus ring 15 is rotated around the optical axis L.

  When the focus ring 15 is turned to the ∞ side, the second lens holder 30 moves to the right, and when the focus ring 15 is turned to the closest side, the second lens holder 30 moves to the left.

  The optical axis of the interchangeable lens is adjusted as follows.

  First, the lens holding frame 60 is arranged on the lens holder 30 accommodated in the lens barrel 10. Further, the lens holding frame 70 is disposed on the lens holder 40 accommodated in the lens barrel 10 (first process).

  Next, four piezoelectric elements 80 </ b> A are arranged on the inner peripheral surface of the lens holder 30 so as to face the outer peripheral surface of the lens holding frame 60. Further, the four piezoelectric elements 80B are arranged on the inner peripheral surface of the lens holder 40 so as to face the outer peripheral surface of the lens holding frame 70 (second step).

  Thereafter, the lens holders 20, 30, 40, 50 are incorporated into the lens barrel 10 (third step).

  Next, an optical measuring instrument is mounted on the mount 12 of the lens barrel 10.

  Thereafter, the driving device 90 is driven while checking the optical performance on the monitor of the optical measuring instrument, and the lens holding frames 60 and 70 are moved in the direction indicated by the arrow a, for example, to adjust the positions of the lenses 60a, 60b, 70a and 70b. (4th process).

  At this time, the positions of the lens holding frames 60 and 70 are adjusted as follows, for example, so that the optical axis does not shift during zooming.

  First, the zoom ring 11 is operated to set a low magnification. The voltage applied to each piezoelectric element 80A, 80B is controlled to adjust the optical axis deviation of the image plane.

  Next, the zoom ring 11 is operated to set a high magnification. The voltage applied to each piezoelectric element 80A, 80B is controlled to adjust the optical axis deviation of the image plane.

  Thereafter, the zoom ring 11 is operated to set it again to a low magnification, and it is confirmed whether or not the optical axis of the imaging plane is deviated. When the optical axis L is deviated, the optical axis deviation of the imaging plane is adjusted again. To do.

  Finally, the optical measuring instrument is removed from the mount 12 of the lens barrel 10, and the lens holding frames 60, 70 are fixed to the lens holders 30, 40 using an adhesive (not shown).

  According to this embodiment, the optical axis can be adjusted from the outside while confirming the optical performance on the monitor of the optical measuring instrument after all the optical members are incorporated in the lens barrel 10, so that the optical axis L Adjustment can be performed easily.

  The number of piezoelectric elements 80A and 80B is not limited to four, and may be three or more.

  In the above-described embodiment, the four piezoelectric elements 80A and 80B are provided at positions facing each other, but one of the facing piezoelectric elements 80A and 80B may be a compression spring, for example. In this way, the number of piezoelectric elements 80A and 80B can be reduced, so that the manufacturing cost can be reduced and driving control for the piezoelectric elements 80A and 80B can be facilitated.

  In the above-described embodiment, the piezoelectric elements 80A and 80B are used as the displacement elements. However, instead of this, an electrostrictive element, a magnetostrictive element, a thermal strain element, or the like can be used.

  Furthermore, in the above embodiment, the four piezoelectric elements 80A are arranged on the inner peripheral surface of the lens holder 30, and then the lens holder 30 is incorporated into the lens barrel 10. However, after the lens holder 30 is incorporated into the lens barrel 10, the lens holder Four piezoelectric elements 80 </ b> A may be arranged on the inner peripheral surface of 30.

FIG. 1A is a conceptual diagram illustrating a cross section of an interchangeable lens according to an embodiment of the present invention before optical axis adjustment, and FIG. 1B is a conceptual diagram illustrating a cross section taken along line 1b-1b of FIG. FIG. 2A is a conceptual diagram showing a cross section of the interchangeable lens according to an embodiment of the present invention after the optical axis is adjusted, and FIG. 2B is a conceptual diagram showing a cross section taken along line 2b-2b of FIG. FIG.

Explanation of symbols

  10: lens barrel, 20-50: lens holder, 60, 70: lens holding frame, 20a, 20b, 50a, 50b, 60a, 60b, 70a, 70b: lens, 80A, 80B: piezoelectric element (displacement element), L :optical axis.

Claims (6)

A first step of disposing an optical member on a lens holder housed in the lens barrel;
After the first step, a second step of disposing a displacement element that moves the optical member based on a given physical quantity around the optical member;
And a third step of adjusting the position of the optical member by driving the displacement element after the second step.   The adjustment method according to claim 1, wherein the moving direction of the optical member is a direction orthogonal to the optical axis of the barrel.   3. The adjustment method according to claim 1, wherein another optical member is accommodated in the lens barrel before the third step.   The adjustment method according to claim 1, wherein the optical member is fixed to the lens holder using an adhesive after the third step.   A lens barrel manufactured using the adjustment method according to claim 1.   A camera comprising the lens barrel according to claim 5.

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