JPH0640909U - Lens barrel - Google Patents

Abstract

(57) [Abstract] [Purpose] The focusing optical system itself does not fall over the optical axis, and it is possible to ensure good optical performance. A focusing outer cylinder 3 is rotatably provided on the inner circumference of a large diameter portion 1c of the fixed barrel 1 and is manually rotated, and a focusing outer cylinder 3 is rotatably provided on the outer circumference of a small diameter portion 1a of the fixed barrel. A focusing inner cylinder 2 integrally and rotatably connected to the outer cylinder 3 around the optical axis, and an outer peripheral surface of a middle diameter portion 1b of the fixed cylinder 1 are provided with an encoder pattern for position recognition. Further, the position detecting means including the pattern member 10 and the sliding member 9 provided on the inner circumference of the focusing outer cylinder 3 and sliding on the pattern member 10 is provided.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a lens barrel for focusing only by moving a part of an optical system, and more particularly to a lens barrel having a built-in distance encoder.

[0002]

[Prior art]

 Conventionally, most distance encoders built into this type of lens barrel are composed of a flexible print plate and a brush, and the brush contacts the pattern of the flexible print plate with a predetermined contact pressure. While sliding, it generates a signal. In such a distance encoder, a brush is fixed to a member that directly rotates the focusing optical system.

[0003]

[Problems to be solved by the device]

 However, in the conventional technique described above, the brush is fixed to the member that directly drives the focusing optical system, and the brush is fixed only at one place on the circumference, so the contact A member that is rotationally driven by the action of pressure causes the optical axis to tilt. For this reason, if the focusing optical system is integrated with the member that is rotationally driven, the focusing optical system itself will tilt with respect to the optical axis, and therefore it is possible to ensure optical performance. It was difficult.

An object of the present invention is to prevent the focusing optical system itself from tilting with respect to the optical axis even when a member that rotationally drives the focusing optical system tilts with respect to the optical axis. It is to provide a lens barrel capable of ensuring optical performance.

[0005]

[Means for Solving the Problems]

 This invention solves the above problems by the following means. In addition, in order to facilitate the understanding, the explanation will be given with the reference numerals corresponding to the embodiments, but the present invention is not limited to this. That is, the lens barrel according to the present invention is a lens barrel that drives a focusing optical system that is a part of an optical system to perform focusing, and has a small diameter portion (1a), a medium diameter portion (1b), and a large diameter portion. A fixed barrel (1) having a portion (1c) and a focusing outer barrel (3) which is rotatably provided on the inner circumference of the large diameter portion (1c) of the fixed barrel and is manually rotated during a manual focusing operation. ), Is rotatably provided on the outer circumference of the small-diameter portion (1a) of the fixed barrel, and is connected to the focusing outer barrel so as to be integrally rotatable only about the optical axis. An encoder pattern for recognizing the position, which is provided on the outer periphery of the focusing inner cylinder (2) for focusing by moving the focusing optical system along the optical axis and the middle diameter portion (1b) of the fixed cylinder. The pattern member (10) on which the aperture is formed and the inner circumference of the focusing outer cylinder (3). There a structure in which a position detection unit consisting of a sliding member (9) to slide over down member.

[0006]

[Action]

 In this invention, a pattern member (flexible printed board 10) is provided on the outer circumference of the middle diameter portion of the fixed barrel, and a sliding member (brush 9) is provided on the inner circumference of the focusing outer barrel to provide the focusing outer barrel and the focusing inner barrel. The (rotatably driven member) is connected so as to be integrally rotatable about the optical axis. Therefore, unlike the conventional case where the sliding member is fixed to the member that directly rotates the focusing optical system, even if the focusing outer cylinder tilts due to the action of the contact pressure of the sliding member, the focusing is prevented. The inner tube does not tilt with respect to the optical axis, and even if the focusing optical system is integrated with the focusing inner tube, the focusing optical system itself does not tilt with respect to the optical axis. It never happens.

[0007]

【Example】

 Hereinafter, the present invention will be described in more detail with reference to the drawings and the like. FIG. 1 is a sectional view showing an embodiment of a lens barrel according to the present invention. In FIG. 1, L1, L2, L3 and L4 are fixed lenses and L5 is a focusing lens. The fixed barrel 1 holds fixed lenses L1, L2, L3, and L4 on its left inner peripheral portion. Further, a male helicoid 1d is provided on the outer peripheral portion of the small diameter portion 1a, and is screwed with a female helicoid 2b provided on the inner peripheral portion of the small diameter portion 2a of the focusing inner cylinder 2.

In the fixed barrel 1, a manual focusing outer barrel 3 is rotatably fitted to the outer peripheral portion of the middle diameter portion 1 b so as to be rotatable around the optical axis. The manual focusing outer barrel 3 is a wall of the fixed barrel 1. Since it is sandwiched between the portion 1f and the wall portion 1e, it is immovable in the optical axis direction and can only rotate. The fixed barrel 1 has an acrylic transparent window 4 fitted on the outer periphery of the large diameter portion 1c, and is engraved on the outer peripheral surface of the manual focusing outer barrel 3 through the hole 1g of the fixed barrel 1. It is possible to read the distance scale 3a. A fixed ring 1 has a diaphragm ring 5 rotatably fitted to an outer peripheral portion in the right direction, and a mount portion 1h engaging with a camera body is provided at an end in the right direction.

The focusing inner cylinder 2 is provided with a female helicoid 2b on an inner peripheral portion of a small diameter portion 2a, and is screwed with a male helicoid 1d provided on an outer peripheral portion of the small diameter portion 1a of the fixing cylinder 1. There is. A focusing lens L5 is held on the inner peripheral portion of the focusing inner tube 2, and when the focusing inner tube 2 rotates, the focusing lens L5 moves along the optical axis by the action of the helicoid. , Focusing is performed. Further, the focusing inner cylinder 2 is provided with a segment gear 2d on the outer peripheral portion of the large diameter portion 2c and meshes with the coupling gear 6. A groove 2e is provided at the left end of the large-diameter portion 2c, and the groove 2e is engaged with the lever portion 3b extending from the manual focusing outer cylinder 3 in the inner peripheral radial direction. The focusing inner cylinder 2 and the manual focusing outer cylinder 3 rotate integrally about the optical axis.

The manual focusing outer cylinder 3 is rotatably fitted around the optical axis to the outer peripheral portion (inner peripheral portion of the large diameter portion 1 c) of the middle diameter portion 1 b of the fixed barrel 1, and the fixed barrel 1 Since it is sandwiched between the wall portion 1f and the wall portion 1e, it is immovable in the optical axis direction and can only rotate. The manual focusing outer cylinder 3 has a lever portion 3b extending in the radial direction of the inner circumference, and is engaged with a groove 2e provided at the left end of the large diameter portion 2c of the focusing inner cylinder 2.

The manual focusing outer cylinder 3 has a brush fixing plate 7 having a brush 9 fixedly mounted in the center thereof fixed by machine screws 8. The brush 9 has an outer periphery of a middle diameter portion 1 b of the fixing cylinder 1. It slides on the pattern of the flexible printed board 10 that is fixed to the portion with a predetermined contact pressure.

The window 4 is a transparent window made of acrylic, and it is possible to read the distance scale 3 a engraved on the outer peripheral surface of the manual focusing outer cylinder 3 through the hole 1 g of the fixed barrel 1. It has become. Here, 5 is an aperture ring, 6 is a coupling shaft for transmitting the driving force from the camera body to the lens barrel during automatic focusing, 7 is a brush fixing plate to which a brush 9 is fixed, and 8 Is a small screw, 9 is a brush, and 10 is a flexible printed board.

Next, the operation of the lens barrel configured as above will be described. During automatic focusing, when the coupling shaft 6 of the lens barrel is rotated by the coupling shaft of the camera body (not shown), the gear portion 6a of the coupling shaft 6 meshes with the segment gear 2d of the focusing inner cylinder 2. Therefore, the focusing inner cylinder 2 rotates. When the focusing inner cylinder 2 rotates, the female helicoid 2b provided on the inner peripheral portion of the small diameter portion 2a and the male helicoid 1d provided on the outer peripheral portion of the small diameter portion 1d of the fixed barrel 1 act to focus. The lens L5 moves along the optical axis for focusing.

On the other hand, when the focusing inner cylinder 2 rotates, the groove 2e provided at the left end of the large diameter portion 2c and the lever portion 3b extending from the manual focusing outer cylinder 3 in the inner radial direction. Are engaged with each other, the focusing inner cylinder 2 and the manual focusing outer cylinder 3 rotate integrally about the optical axis. When the manual focusing outer cylinder 3 rotates, the brush 9 is fixed to the fixing barrel because the brush fixing plate 7 to which the brush 9 is fixed is fixed by the machine screw 8 in the central portion of the manual focusing outer cylinder 3. The flexible printed board 10 fixed to the outer peripheral portion of the medium diameter portion 1b is slid on the pattern by a predetermined contact pressure, and distance information corresponding to the rotation angle is transmitted to the camera body.

At the time of manual focusing, when the rubber ring 11 mounted on the outer peripheral portion of the manual focusing outer cylinder 3 is manually rotated, the brush 9 is fixed to the central portion of the manual focusing outer cylinder 3. Since the fixed brush fixing plate 7 is fixed by the machine screw 8, the brush 9 is fixed on the pattern of the flexible printed board 10 fixed to the outer peripheral portion of the medium diameter portion 1b of the fixing cylinder 1 at a predetermined contact pressure. And slide to transmit distance information according to the rotation angle to the camera body.

When the manual focusing outer cylinder 3 rotates, it extends in the inner peripheral radial direction from the groove 2e provided at the left end of the large diameter portion 2c of the focusing inner cylinder 2 and the manual focusing outer cylinder 3. The focusing inner cylinder 2 and the manual focusing outer cylinder 3 are integrally rotated about the optical axis because they are engaged with the lever portion 3b that is being rotated. Then, when the focusing inner cylinder 2 rotates, by the action of the female helicoid 2b provided on the inner peripheral portion of the small diameter portion 2a and the male helicoid 1d provided on the outer peripheral portion of the small diameter portion 1d of the fixed barrel 1, The focusing lens L5 moves along the optical axis to perform focusing.

At this time, since the brush 9 is fixed at only one place on the circumference of the manual focusing outer cylinder 3, the contact pressure causes the manual focusing outer cylinder 3 to move with respect to the optical axis. May cause a fall. However, by rotating the focusing optical system (focusing lens L5) along the optical axis to perform focusing, a focusing inner cylinder 2 and a manual focusing outer cylinder that is manually rotated during manual focusing. 3 by a groove 2e provided at the left end of the large diameter portion 2c of the focusing inner cylinder 2 and a lever portion 3b extending from the manual focusing outer cylinder 3 in the radial direction of the inner circumference. Is rotatably engaged with. For this reason, even if the manual focusing outer cylinder 3 tilts with respect to the optical axis, the focusing inner cylinder 2 is not affected. Good optical performance can be secured without causing a fall.

[0018]

[Effect of device]

 As described above in detail, in the present invention, the pattern member is provided on the outer circumference of the middle diameter portion of the fixed barrel, the sliding member is provided on the inner circumference of the focusing outer barrel, and the focusing outer barrel and the focusing inner barrel are Since it is connected so that it can only rotate integrally around the optical axis, even if the focusing outer cylinder tilts due to the contact pressure of the sliding member, the focusing inner cylinder tilts with respect to the optical axis. Will not occur. Therefore, even if the focusing optical system is integrated with the focusing inner cylinder, the focusing optical system itself does not tilt with respect to the optical axis, and good optical performance can be secured.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a lens barrel according to the present invention.

[Explanation of symbols]

 L1, L2, L3, L4 Fixed lens L5 Focusing lens 1 Fixed barrel 1d Male helicoid 2 Focusing inner barrel 2b Female helicoid 2d Segment gear 2e Groove 3 Manual focusing outer barrel 3a Distance scale 3b Lever section 4 Acrylic window 5 Aperture ring 6 Coupling gear 6a Gear part 7 Brush fixing plate 8 Machine screw 9 Brush 10 Flexible printed board 11 Rubber ring

Claims (1)

[Scope of utility model registration request] 1. A lens barrel for driving a focusing optical system, which is a part of an optical system, for focusing; a fixed barrel having a small diameter portion, a medium diameter portion, and a large diameter portion; A focusing outer cylinder rotatably provided on the inner circumference of the large diameter portion and manually rotated during a manual focusing operation; and a focusing outer cylinder rotatably provided on the outer circumference of the small diameter portion of the fixed barrel. A focusing inner cylinder that is integrally rotatable only about the optical axis and that rotates to move the focusing optical system along the optical axis for focusing; and a middle diameter of the fixed cylinder. A pattern member provided on the outer circumference of the portion, on which an encoder pattern for position recognition is formed, and provided on the inner circumference of the focusing outer cylinder,
A lens barrel comprising: a position detecting unit including a sliding member that slides on the pattern member.