JP2008180762A - Optical axis adjustment device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical axis adjustment device capable of stably adjusting the optical axis 44 of fourth group lenses 22a and 22b. <P>SOLUTION: The optical axis adjustment device includes: a fourth group frame 60 supporting the fourth group lenses 22a and 22b; a fourth group holder 66 supporting the fourth group frame 60 so as to be movable within a plane perpendicular to the optical axis 44 of the fourth group lenses 22a and 22b; a plate spring 64 fixed to the fourth group holder 66 and regulating the movement of the fourth group frame 60 in the direction of the optical axis 44 of the fourth group lenses 22a and 22b; an energization means supported by the fourth group holder 66 and energizing the fourth group frame 60 in a predetermined direction within a plane perpendicular to the optical axis 44 of the fourth group lenses 22a and 22b; and a plurality of adjustment screws 46 supported by the fourth group holder 66 and presses the fourth group frame 60 within a plane perpendicular to the optical axis 44 of the fourth lenses 22a and 22b, in a direction against the component of force of the energization means. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical axis adjusting device used for a lens barrel that supports an optical lens used in a digital still camera or the like.

  In recent years, with the popularization of digital single-lens reflex cameras, lens barrels used for interchangeable lenses are required to support the lens group with high accuracy and to improve optical performance.

  A conventional lens barrel will be described below. FIG. 3 is a cross-sectional view showing a main part configuration of a conventional lens barrel.

  In FIG. 3, reference numeral 10 denotes a first group lens, which is supported by the first group frame 12. Reference numeral 14 denotes a second group lens supported by the second group frame 16. Reference numeral 18 denotes a third group lens, which is supported by the third group frame 20. Reference numerals 22 a and 22 b denote 4 group lenses, which are supported by the 4 group frame 24.

  Reference numerals 26a and 26b denote cam cylinders, and the cam cylinders 26a and 26b are relatively rotatable. Three first group cam followers 28 are provided on the inner periphery of the first group frame 12, three second group cam followers 30 are provided on the outer periphery of the second group frame 16, and three third groups are provided on the outer periphery of the third group frame 20. Cam followers 32 are respectively provided and engaged and supported in cam grooves 34, 36, and 38 corresponding to the cam cylinders 26a and 26b, respectively.

  When the cam cylinders 26a and 26b are relatively rotated, the positions of the cam grooves 34, 36, and 38 are relatively changed, and accordingly, the positions of the first group frame 12, the second group frame 16, and the third group frame 20 are relatively changed. The distance between the lenses of the first group lens 10, the second group lens 14, and the third group lens 18 changes, and the focal length can be changed.

  The fourth group frame 24 is fixed to the third group frame 20 together with the fourth group holder 42 by screws 40 at three places, and the distance between the lenses of the fourth group lenses 22a and 22b and the third group lens 18 does not change. However, if the value of the deviation e between the optical axis 43 of the first group lens 10, the second group lens 14, and the third group lens 18 and the optical axis 44 of the fourth group lenses 22a and 22b is not as close as possible to 0, the lens barrel is obtained. Designed to prevent performance. Accordingly, the position of the fourth group frame 24 is adjusted by the adjusting screw 46 so that the value of the optical axis deviation e is brought close to zero.

  This adjustment will be described with reference to FIGS. FIG. 4 is an enlarged cross-sectional view of the third group frame 20, the fourth group holder 42, and the fourth group frame 24. FIG. 5 is a perspective view of the lens barrel viewed from the direction of arrow A shown in FIG.

  In order to adjust the optical axis 43 and the optical axis 44 without changing the inter-lens distance between the third group lens 18 and the fourth group lenses 22a and 22b, the fourth group frame 24 is pressed in the arrow A direction. It is necessary to move in the directions of arrows X1, X2, Y1, and Y2 shown in FIG.

  The three screws 40 for fixing the fourth group frame 24 are screwed into the third group frame 20 through the fourth group frame 24 and the fourth group holder 42 through the spring washer 48 and the flat washer 50. The screw 40 is not tightened until the spring washer 48 is crushed, but is tightened until it is deformed to the extent that a spring effect occurs. In this state, since the fixing hole 52 of the fourth group frame 24 has a gap with respect to the outer diameter of the screw 40, the fourth group frame 24 can move in the directions of arrows X1, X2, Y1, and Y2 shown in FIG. Is possible.

  Two adjusting screws 46a and 46b are inserted orthogonally into the fourth group holder 42, and are structured to move in the directions of arrows X1, X2, Y1, and Y2 depending on the rotation direction. The tips of the adjusting screws 46a and 46b are in contact with the fourth group frame 24. When the adjusting screw 46a is tightened in this state, the fourth group frame 24 moves in the direction of the arrow Y1, and when the adjusting screw 46b is tightened, the fourth group frame 24 is moved to the arrow. Move in the X1 direction.

  A compression spring 54 is provided between the fourth group holder 42 and the fourth group frame 24, and the fourth group frame 24 is pressed against the two adjustment screws 46 a and 46 b by the repulsive force of the compression spring 54. . Accordingly, when the adjustment screw 46a is loosened, the fourth group frame 24 moves in the direction of arrow Y2, and when the adjustment screw 46b is loosened, the fourth group frame 24 moves in the direction of arrow X2.

  Here, in order to adjust the optical axis 43 of the third group lens 18 and the optical axis 44 of the fourth group lenses 22a and 22b to coincide with each other, the two adjustment screws 46a and 46b are rotated to move the fourth group frame 24 to the arrow. The optical axis 43 and the optical axis 44 are adjusted by moving in the X1, X2, Y1, and Y2 directions.

A configuration of the same kind is disclosed in Patent Document 1.
Japanese Utility Model Publication No. 61-11412

  However, in the conventional configuration, it is difficult to balance the pressing force of the spring washer 48 for pressing the fourth group frame 24 in the direction of arrow A and the repulsive force of the compression spring 54.

  That is, if the three screws 40 are tightened too much, the fourth group frame 24 will not move in the directions of the arrows Y1 and X1 even if the adjusting screws 46a and 46b are tightened. Even if the adjusting screws 46a and 46b are loosened, the fourth group frame 24 does not move in the directions of the arrows Y2 and X2 by the repulsive force of the compression spring 54.

  Conversely, if the three screws 40 are loosened too much, the fourth group frame 24 cannot be pressed sufficiently in the direction of arrow A, so that the optical axis 44 of the fourth group lenses 22a and 22b tilts or the position of the fourth group holder 42 moves. As a result, the fourth group frame 24 moves and the optical axes 44 of the fourth group lenses 22a and 22b shift.

  Furthermore, if the tightening balance of the three screws 40 is lost, the fourth group frame 24 does not move in the directions of the arrows X1, X2, Y1, and Y2 according to the rotation of the adjusting screws 46a and 46b, and rotates around the fixing hole 52. Had a point.

  The present invention solves the above-described conventional problems, and an object thereof is to provide an optical axis adjusting device capable of stably adjusting the optical axes 44 of the fourth group lenses 22a and 22b.

  In order to solve the above-mentioned problems, an optical axis adjusting device according to the present invention includes a lens frame that supports at least one lens, and a holder that supports the lens frame so as to be movable in a plane perpendicular to the optical axis of the lens. And a restricting means that is fixed to the holder and restricts the movement of the lens frame in the optical axis direction of the lens; and the lens frame supported by the holder is in a predetermined direction within a plane perpendicular to the optical axis of the lens. And a plurality of adjustment means for pressing the lens frame supported by the holder in a direction against a component force of the urging force of the urging means in a plane perpendicular to the optical axis of the lens. It is characterized by comprising.

  The optical axis adjusting device according to the present invention includes a lens frame that supports at least one lens, a holder that supports the lens frame so as to be movable in a plane perpendicular to the optical axis of the lens, and is fixed to the holder. And a plurality of restricting means for restricting movement of the lens frame in the optical axis direction of the lens, and a plurality of members that are supported by the holder and bias the lens frame in a predetermined direction within a plane perpendicular to the optical axis of the lens. Urging means, and a plurality of adjusting means that are supported by the holder and press the lens frame in a direction against the urging force of the urging means in a plane perpendicular to the optical axis of the lens. It is characterized by.

  The restricting means may be a plurality of leaf springs. The holder and the restricting means may be integrally formed. The urging means may be a compression spring, a leaf spring, or an extension spring. The adjusting means may be an adjusting screw.

  As described above, according to the present invention, since the lens frame for adjusting the optical axis of the lens is adjusted in a state of being stably pressed by the restricting means, the optical axis of the lens is inclined. There is nothing. In addition, since the lens frame moves smoothly in proportion to the adjustment amount of the adjustment means, there is an effect that the lens optical axis adjustment is highly accurate and the adjustment time is shortened.

(Embodiment)
Hereinafter, embodiments of the present invention will be described with reference to FIGS. Since the configuration of the lens barrel is the same as that shown in FIG. 3 described in the background art, description thereof is omitted. FIG. 1 is an enlarged cross-sectional view of the third group frame 20, the fourth group holder 66, and the fourth group frame 60 in the embodiment of the present invention. 2 is a perspective view of the lens barrel viewed from the direction of arrow A shown in FIG.

  The fourth group frame 60 that supports the fourth group lenses 22a and 22b is placed on the fourth group holder 66, and is convex by three leaf springs 64 fixed to the third group frame 20 together with the fourth group holder 66 by three screws 40. The part 62 is pressed in the direction of arrow A.

  Here, in order to adjust the optical axis 43 and the optical axis 44 so that the distance between the lenses of the third group lens 18 and the fourth group lenses 22a and 22b does not change, the fourth group frame 60 is pressed in the direction of arrow A. In this state, it is necessary to move in the directions of arrows X1, X2, Y1, and Y2 shown in FIG.

  Two adjusting screws 46a and 46b are inserted orthogonally into the fourth group holder 66, and are structured to move in the directions of arrows X1, X2, Y1, and Y2 depending on the rotation direction. The tips of the adjusting screws 46a and 46b are in contact with the fourth group frame 60. When the adjusting screw 46a is tightened in this state, the fourth group frame 60 moves in the direction of the arrow Y1, and when the adjusting screw 46b is tightened, the fourth group frame 60 is moved to the arrow. Move in the X1 direction.

  A compression spring 54 is provided between the fourth group holder 66 and the fourth group frame 60, and the fourth group frame 60 is pressed against the two adjustment screws 46 a and 46 b by the component force of the repulsive force of the compression spring 54. . Therefore, when the adjustment screw 46a is loosened, the fourth group frame 60 moves in the direction of arrow Y2, and when the adjustment screw 46b is loosened, the fourth group frame 60 moves in the direction of arrow X2.

  Here, in order to adjust the optical axis 43 of the third group lens 18 and the optical axis 44 of the fourth group lenses 22a and 22b to coincide, the two adjustment screws 46a and 46b are rotated to move the fourth group frame 60 to the arrow. The optical axis 43 and the optical axis 44 are adjusted by moving in the X1, X2, Y1, and Y2 directions.

  For example, when the adjustment screw 46a is tightened, the adjustment screw 46a moves in the arrow Y1 direction, and the fourth group frame 60 moves in the arrow Y1 direction against the component force of the compression spring 54 in the arrow Y2 direction. Further, when the fourth group frame 60 is moved in the arrow Y2 direction, the adjustment screw 46a is loosened, and the compression spring 54 is pushed back in the arrow Y2 direction by the component force in the arrow Y2 direction. At this time, the fourth group frame 60 has no problem in movement because the convex portion 62 is merely pressed by the leaf spring 64.

  The pressing force of the leaf spring 64 in the direction of arrow A is determined by the initial deflection amount, and is stable because it does not depend on the degree of tightening of the screw 40, and can balance the force with the compression spring 54. Easy. Further, since the fourth group holder 66 is fixed to the third group frame 20 by the screw 40 together with the leaf spring 64, there is no fear of moving by adjustment.

  As described above, in the embodiment of the present invention, when the optical axis 44 of the fourth group lenses 22a and 22b provided in the fourth group frame 60 is adjusted, the convexity of the fourth group frame 60 by the three leaf springs 64 is adjusted. Since the part 62 is pressed in the direction of arrow A, the movement during adjustment is smooth. Further, since the fourth group holder 66 on which the fourth group frame 60 is placed is fixed independently to the third group frame 20, there is no fear of moving due to the influence of adjustment. Therefore, an excellent effect that the optical axis can be adjusted accurately in a short time can be obtained.

In the embodiment of the present invention, the fourth group frame 60 is the lens frame of the present invention. The fourth group holder 66 is a holder of the present invention. The leaf spring 64 is a regulating means of the present invention. The compression spring 54 is an urging means of the present invention. The adjusting screws 46a and 46b are adjusting means of the present invention.
(Other embodiments)
In the above-described embodiment of the present invention, the leaf spring 64 presses the fourth group frame 60 in the direction of arrow A, but the fourth group lenses 22a and 22b of the fourth group frame 60 move in the direction of the optical axis 44. Since it only needs to be able to regulate, elasticity is not necessarily required.

  In addition, the leaf spring 64 is fixed to the third group frame 20 through the fourth group holder 66 with the screw 40, but these may be integrally formed with a resin material or the like. In that case, the fourth group frame 60 is placed on the fourth group holder 66 and then rotated to rotate the fourth group frame 60 between the regulating means formed integrally with the fourth group holder 66 and the main body of the fourth group holder 66. What is necessary is just to comprise so that the convex part 62 may be pinched | interposed. Thereby, the number of parts and the number of assembly steps can be reduced.

  In the above embodiment of the present invention, the fourth group frame 60 is pressed against the two adjusting screws 46a and 46b by the repulsive force of the compression spring 54. However, instead of the compression spring 54, a plate spring is used. It may be used. As a result, the space occupied by the biasing means can be reduced.

  Further, an extension spring may be used instead of the compression spring 54. Since the extension spring generates a traction force in the direction opposite to that of the compression spring 54, the adjusting screws 46a and 46b must be inserted at positions opposite to the positions shown in FIG. That is, in FIG. 2, the adjustment screw 46a must be inserted from the top, and the adjustment screw 46b must be inserted from the left.

  A plurality of biasing means such as a compression spring 54, a leaf spring, and an extension spring may be provided. In that case, a pair of urging means and adjusting means may be arranged in the directions of arrows X1 and X2, and a pair of urging means and adjusting means may be arranged in the directions of arrows Y1 and Y2.

  According to the present invention, since the optical axis adjustment of the lens can be performed with high accuracy and the adjustment time can be shortened, the interchangeable lens of a digital single lens reflex camera, a film type single lens reflex camera, a digital still camera, and a lens barrel of a film type camera can be used. Useful to apply.

Sectional drawing of the optical-axis adjustment apparatus in embodiment of this invention The perspective view of the optical-axis adjustment apparatus in embodiment of this invention Sectional view of a conventional lens barrel Sectional view of a conventional optical axis adjustment device Perspective view of a conventional optical axis adjustment device

Explanation of symbols

18 3 group lens 20 3 group frame 22a, 22b 4 group lens 40 screw 43, 44 Optical axis 46 Adjustment screw 60 4 group frame 62 Convex part 64 Leaf spring 66 4 group holder

Claims (8)

A lens frame supporting at least one lens;
A holder for supporting the lens frame movably in a plane perpendicular to the optical axis of the lens;
A restricting means for restricting movement of the lens frame in the optical axis direction of the lens frame fixed to the holder;
A biasing unit that is supported by the holder and biases the lens frame in a predetermined direction within a plane perpendicular to the optical axis of the lens;
A plurality of adjusting means for pressing the lens frame supported by the holder in a direction against a component force of the urging force of the urging means in a plane perpendicular to the optical axis of the lens;
With
An optical axis adjusting device characterized by that. A lens frame supporting at least one lens;
A holder for supporting the lens frame movably in a plane perpendicular to the optical axis of the lens;
A restricting means for restricting movement of the lens frame in the optical axis direction of the lens frame fixed to the holder;
A plurality of urging means for urging the lens frame supported by the holder in a predetermined direction within a plane perpendicular to the optical axis of the lens;
A plurality of adjusting means for pressing the lens frame supported by the holder in a direction against the urging force of the urging means in a plane perpendicular to the optical axis of the lens;
With
An optical axis adjusting device characterized by that. The regulating means is
A plurality of leaf springs,
The optical axis adjusting device according to claim 1, wherein The holder and the regulating means are:
Formed integrally,
The optical axis adjusting device according to any one of claims 1 to 3, wherein The biasing means is
A compression spring,
5. The optical axis adjusting device according to claim 1, wherein The biasing means is
A leaf spring,
5. The optical axis adjusting device according to claim 1, wherein The biasing means is
An extension spring,
5. The optical axis adjusting device according to claim 1, wherein The adjusting means includes
Adjustment screw,
The optical axis adjusting device according to any one of claims 1 to 7, wherein

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