JP5807837B2 - Lens barrel and optical device - Google Patents

Description

  The present invention relates to a lens barrel and an optical device.

  Conventionally, there has been known a lens barrel that prevents flare by moving a flare stop in the optical axis direction relative to a third lens group (a lens group disposed at the rearmost side of the cam cylinder) ( (See the following patent document).

Japanese Patent Laid-Open No. 5-188274

  When a dedicated flare stop is used to prevent flare, not only the mounting of the flare stop to the lens barrel is required, but also the parts related to the flare stop are required, which increases the manufacturing cost. . In addition, since the arrangement of parts related to the flare stop is restricted, the degree of freedom in design is lost.

  The present invention has been made in view of such circumstances, and the object thereof is to provide a lens barrel and an optical device that can reduce manufacturing costs while preventing flare and can increase the degree of design freedom. is there.

In order to solve the above-mentioned problem, the invention according to claim 1 is a first lens and a second lens which are sequentially arranged in order from the subject side , and a lens barrel body containing the first lens and the second lens. An electric substrate provided between the first lens and the second lens in the barrel main body, provided between the first lens and the second lens in the barrel main body, and the and a variable throttle unit provided from an electric substrate to the object side, the electrical substrate is incident on the lens barrel body, does not contribute to the imaging of the variable throttle unit light you pass through openings in the It is arranged at a position where light can be blocked.

According to a second aspect of the present invention, in the lens barrel according to the first aspect, a slope inclined with respect to an optical axis of an optical system including the first lens and the second lens is formed on a side surface of the electric substrate. It is formed.

  According to a third aspect of the present invention, in the lens barrel according to the first or second aspect, a light shielding line is formed on a side surface of the electric substrate.

  According to a fourth aspect of the present invention, in the lens barrel according to any one of the first to third aspects, the electric substrate is a glass epoxy substrate.

  According to a fifth aspect of the present invention, in the lens barrel according to any one of the first to third aspects, the electric substrate is a laminated substrate.

  According to a sixth aspect of the present invention, in the lens barrel according to any one of the first to fifth aspects, an antireflection paint is applied to the electric substrate.

  A seventh aspect of the present invention is an optical device comprising the lens barrel according to any one of the first to sixth aspects.

  According to the present invention, the manufacturing cost can be reduced while preventing flare, and the degree of design freedom can be expanded.

FIG. 1 is a conceptual diagram showing a cross section of the upper half of a lens barrel according to an embodiment of the present invention. FIG. 2A is a partially enlarged view of FIG. 1, and FIG. 2B is a conceptual diagram showing a cross section of a printed board on which a light shielding line is formed.

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

  FIG. 1 is a conceptual diagram showing a cross section of the upper half of a lens barrel 100 according to an embodiment of the present invention, and FIG. 2A is a partially enlarged view of FIG.

  A lens mount 1, which is a joining mechanism with a camera body (optical device) 200, is provided at the rear end of the substantially cylindrical fixed barrel (lens barrel body) 2 of the lens barrel 100.

  The lens barrel 100 incorporates two sets of lenses L1 and L2 constituting a photographing optical system (optical system). The front side (subject side) lens L1 is attached to the inner diameter 2a of the fixed barrel 2, and the rear side (imaging surface 20 side) lens L2 is attached to the inner diameter 2d of the fixed barrel 2. One surface R2 of the lens L1 is in contact with the barrel portion 2b, and the other surface R1 is urged toward the lens L2 by the press ring 11. A screwing portion 11 a of the holding ring 11 is screwed into a screwing portion 2 c formed on the inner peripheral surface of the fixed barrel 2.

  In addition, one surface R3 of the lens L2 is in contact with the barrel portion 2e, and the other surface R4 is urged toward the lens L1 by the pressing ring 12. A screwing portion 12 a of the holding ring 12 is screwed into a screwing portion 2 f formed on the inner peripheral surface of the fixed barrel 2.

  The lens barrel 100 includes a variable aperture unit 30 and an electric unit 40, and these units 30 and 40 are located between the lens L1 and the lens L2.

  The variable aperture unit 30 includes a so-called honeycomb 3 that rotatably supports the aperture blade 5 via the dowel 6, and a cam groove 4 b that engages with the dowel 7 provided on the aperture blade 5. A so-called arrow wheel 4 that transmits a driving force to the aperture blade 5 to change the aperture diameter of the aperture blade 5 is provided. The outer diameter 4a of the arrow wheel 4 is rotatably fitted to the inner diameter 3b of the honeycomb 3. The arrow wheel 4 is driven by, for example, a motor (not shown) in accordance with an instruction from the camera body (or lens barrel).

  The beehive 3 is fitted into the inner diameter 2 g of the fixed barrel 2, abuts against the body mounting surface 2 h, and is fixed to the fixed barrel 2 with screws 8. The honeycomb 3 is formed with a fitting hole 3e into which a dowel 6 fixed to the diaphragm blade 5 is fitted. The beehive 3 is formed with an inclined surface 3d that continues to the side surface 3c. The slope 3d is on the imaging surface 20 side. By forming the slope 3d, the area of the side surface 3c can be made very small, and the reflected light at the side surface 3c can be reduced. The aperture opening F value is determined by the end surface 3f (front end portion) of the side surface 3c of the honeycomb 3.

  The electric unit 40 includes a printed board (electric board) 9 and electric components 9a and 9b mounted on both sides of the printed board 9, respectively. The thickness of the printed board 9 is about 0.8 mm, and the printed board 9 has an annular shape. The opening surface of the printed circuit board 9 is orthogonal to the optical axis L. The printed board 9 is a rigid board such as a glass epoxy board or a laminated board. As the printed board 9, not only a rigid board but also a flexible board (FPC) can be used.

  The printed circuit board 9 is fitted into the inner diameter 2 i of the fixed barrel 2. The outer diameter 9c of the printed circuit board 9 is in contact with the inner diameter 2i. The rear surface of the printed circuit board 9 is in contact with the body mounting surface 2j. The printed circuit board 9 is fixed to the fixed barrel 2 with screws 10. The printed circuit board 9 is disposed at a position (see FIG. 1) where light that does not contribute to image formation among light incident on the fixed barrel 2 can be blocked so that flare does not occur.

  Further, the printed circuit board 9 is formed with an inclined surface 9e connected to the side surface 9d. The slope 9e is on the imaging surface 20 side. An antireflection paint (not shown) such as a black matte paint is applied to the side face 9d and the slope 9e. The reflectance of the paint is lower than the reflectance of the inner wall of the fixed barrel 2. By forming the inclined surface 9e on the printed circuit board 9, the area of the side surface 9d becomes very small, so that there is almost no surface reflection on the side surface 9d, a high antireflection effect is obtained, and flare is further prevented.

  In addition, if a light shielding line (not shown) can be formed on the side surface 9d of the printed circuit board 9, the antireflection effect is enhanced, and flare can be more reliably prevented.

  Further, if the area of the side surface 9d can be reduced to such an extent that the side surface 9d becomes linear (knife edge shape) when viewed from the optical axis L, the antireflection effect is enhanced, and flare can be more reliably prevented.

  Further, the light shielding lines 50 may be formed on the side surface 19d of the printed circuit board (electrical board) 19 as shown in FIG.

  FIG. 2B is a conceptual diagram showing a partial cross section of a printed circuit board 19 of a lens barrel according to a modification of the present invention.

  The cross-sectional shape of the side surface 19d has a sawtooth shape, and the light incident on the side surface 19d out of the light incident on the lens barrel 100 is not reflected to the imaging surface 20. Therefore, flare can be prevented by the light shielding line 50 in the same manner as the slope 9e is formed. After forming the light shielding line 50, an antireflection coating is applied to the side surface 19d.

  An effective light ray incident on the lens barrel 100 (light ray incident from the front side of the lens barrel 100 and reaching the imaging surface 20) will be described with reference to FIG.

  In FIG. 1, among the light rays K1 to K7 that pass through the lenses L1 and L2 of the lens barrel 100, the effective light rays that are irradiated on the outermost side in the diagonal direction of the imaging surface 20 formed on the imaging surface 20 are illustrated. . K1, K2, K3, K4, K5, K6, and K7 are a light beam incident on the lens L1 from the front side of the lens barrel 100, a light beam that passes through the surface R1 of the lens L1 and goes straight through the lens 1, and the lens L1. Passing through the surface R2 and passing through the end surface 3f of the side surface 3c of the honeycomb 3, the light beam passing through the aperture blade 5 and the end surface 9f of the side surface 9d of the printed circuit board 9, and passing through the end surface 9f of the side surface 9d of the printed circuit board 9. A light beam incident on the surface R3, a light beam passing through the surface R3 of the lens L2 and traveling straight through the lens 2, and a light beam passing through the surface R4 of the lens L2 and incident on the imaging surface 20.

  Of the light that passes through the lens barrel 100 and enters the imaging surface (or film surface) 20, unnecessary light other than the light necessary to form the subject image is blocked by the printed circuit board 9, and a clear image is obtained. Flares that adversely affect formation are prevented.

  According to this embodiment, since a dedicated flare stop is not used to prevent flare, the flare stop mounting process and parts related to the flare stop are unnecessary, and the number of parts of the lens barrel 100 can be reduced. Manufacturing cost can be reduced. In addition, the problem of how to arrange components related to the flare stop can be solved, and the degree of freedom in design can be expanded.

  In the above-described embodiment, only one printed circuit board 9 is disposed between the lens L1 and the lens L2. However, the light that does not contribute to image formation among the light incident on the fixed barrel 2 can be blocked. For example, a plurality of printed circuit boards 9 may be arranged on the front side of the lens L1 or the rear side of the lens L2.

  Further, in the above-described embodiment, the slope 9e is formed on the printed board 9, and the black matte paint is applied to the side surface 9d and the slope 9e, or the shading line 50 is formed on the side surface 9d, and the black matte paint is applied to the side surface 19d. However, the problems of the present invention can be solved without these configurations.

  2: fixed barrel (lens barrel main body), 9, 19: printed circuit board (electrical board), 9e: slope, 50: light shielding line, 100: lens barrel, 200: camera body (optical device), L: optical axis , L1, L2: lenses.

Claims (7)

A first lens and a second lens that are sequentially arranged from the subject side;
A lens barrel body containing the first lens and the second lens;
An electric substrate provided between the first lens and the second lens in the barrel body;
A variable aperture unit provided between the first lens and the second lens in the barrel main body, and provided on the subject side from the electric substrate;
The lens barrel, wherein the electric substrate is disposed at a position where light that does not contribute to image formation out of light that enters the barrel main body and passes through the opening of the variable aperture unit can be blocked. The lens barrel according to claim 1 , wherein an inclined surface that is inclined with respect to an optical axis of an optical system including the first lens and the second lens is formed on a side surface of the electric substrate.   3. The lens barrel according to claim 1, wherein a light shielding line is formed on a side surface of the electric substrate.   The lens barrel according to claim 1, wherein the electric substrate is a glass epoxy substrate.   The lens barrel according to claim 1, wherein the electric substrate is a laminated substrate.   The lens barrel according to claim 1, wherein an antireflection paint is applied to the electric substrate.   An optical apparatus comprising the lens barrel according to claim 1.

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