JPH09297257A - Zoom lens - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a zoom lens which is easily focused on a subject at a specified distance and constituted so that the divergence of focus is not caused by zooming operation. SOLUTION: An aperture 33b is formed on a focusing lens barrel 33 moving a focusing lens frame 30, and a leaf spring 51 is attached to the aperture 33b. Grooves 39a and 39b in which the spring 51 is engaged in the case the frame 30 is focused on the subject at the specified distance are formed on the outer peripheral surface of a fixed barrel 28. Even when a zoom lens barrel 31 is operated in a state where the spring 51 is engaged with the groove 39a or 39b, the spring 51 is moved inside the groove, so that the divergence of focus is not caused.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a zoom lens which can be easily focused and is prevented from being out of focus by a zooming operation.

[0002]

2. Description of the Related Art As a zoom lens used in a compact camera or the like, a two-group zoom system having a simple structure is used. This two-group zoom lens includes a focus lens, a zoom lens, a fixed barrel that holds the zoom lens so as to be movable along the optical axis direction, and a rotatably assembled outer periphery of the fixed barrel. It includes a focus lens barrel that moves along the axial direction and a zoom lens barrel that moves the focus lens barrel and the zoom lens along the optical axis direction.

Focusing is performed by moving the focus lens in the optical axis direction due to rotation of the focus lens barrel, and movement of the zoom lens and focus lens barrel in the optical axis direction due to rotation of the zoom lens barrel results in focal length. Is changing.

[0004]

However, the above-mentioned 2)
When a group-structure zoom lens is used in a low-cost optical device, focusing is done manually, but with an optical device that focuses only on objects at multiple specific distances, focusing is troublesome. It was In addition, if the zoom lens barrel is rotated after focusing by rotating the focus lens barrel, the focus lens barrel may rotate and the focus may be deviated, and the focus adjustment must be performed again after the zooming operation. It was very troublesome.

The present invention is intended to solve the above-mentioned problems, and provides a zoom lens capable of easily focusing on an object at a specific distance and preventing the focus from being displaced by a zooming operation. The purpose is to

[0006]

In order to solve the above-mentioned problems, the zoom lens according to claim 1 has a structure in which the zoom lens barrel rotates at a position where the focus lens matches at least two or more different distance objects. The focus mechanism is provided to mechanically stop the rotation of the focus lens barrel so that the position does not shift.

The zoom lens according to a second aspect of the present invention is, as a focusing mechanism, a leaf spring attached to the focus lens barrel and abutting on the outer peripheral surface of the fixed barrel, and an outer peripheral surface of the fixed barrel along the optical axis direction. And a groove into which a leaf spring enters during the rotation of the focus lens barrel.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The zoom lens of the present invention will be described below by taking an image input device as an example. FIG. 2 shows a state when the image input device 2 is not used. The image input device 2 includes a main body 3 having a vertical structure and the main body 3.
It is composed of a pair of arm stands 4 and 5 that are pivotally attached to both side surfaces of the main body 3 and can be raised and lowered with respect to the main body portion 3, and a head portion 6 that is rotatably assembled to the upper portion of the main body portion 3. .

As shown in FIG. 3, a zoom lens 7 and an image pickup device including a CCD 8 and various electric circuits are incorporated in the main body 3. Further, on the side surface and the front surface of the main body portion 3, an image output terminal 9 and a switching dial 1 for switching the focal length of the zoom lens 7 according to the imaged object.
0, a zoom dial 11 and the like are provided. The zoom lens 7 is arranged in the main body portion 3 toward the upper head portion 6.

The head portion 6 is formed with an image pickup opening 13 continuous with the zoom lens 7 in the main body portion 3. Further, it is rotatable with respect to the main body 3, and the orientation of the image can be easily changed. A slot 15 into which a film carrier 14 (see FIG. 4) holding a developed photographic film cut into pieces is inserted is formed in the upper portion of the head portion 6. The film inserted into the slot 15 is formed. The carrier 14 faces the zoom lens 7 across the imaging aperture 13.

At the top of the head portion 6, hinges 17, 18 are provided.
The lamp houses 19 and 20 that can be freely opened and closed are assembled. Lamps 21 and 22 are incorporated in the lamp houses 19 and 20, respectively, and are used when illuminating an object to be imaged such as a developed photographic film or a print photograph.

The arm stands 4 and 5 are plate-shaped, and are pivotally attached to each other so as to sandwich the main body 3 therebetween. The tips of the arm stands 4 and 5 are
It is elongated so as to be located below the lower surface of the main body portion 3 when not in use.

The arm stands 4 and 5 are the image input device 2
When not in use, the image input device 2 is downsized because it is laid down with respect to the main body 3. Further, as shown in FIG. 4, when capturing an image of a developed photographic film,
Opened small with respect to the main body 3, both arm stands 4,
The tip end of 5 and the lower surface of the main body 3 are grounded to support the image input device 2 in an upright state. At this time, the lamp houses 19 and 20 are closed with respect to the head portion 6 and illuminate the photographic film 24 in the film carrier 14 inserted into the slot 15 through the imaging opening 13.

Further, when photographing a reflection original such as a print photograph, as shown in FIG. 5, both arm stands 4 and 5 are used.
Is largely opened from the main body 3, and the front end supports the main body 3 in an inverted state. Then, the print photograph 26 is arranged below the head portion 6, and an image is taken through the imaging opening 13. At this time, the lamp houses 19 and 20 are opened with respect to the head portion 6, and the print photograph 6 and the like are illuminated in this state. The arm stands 4 and 5 are locked in their respective positions.

As shown in FIGS. 1, 3 and 6, the zoom lens 7 includes a fixed barrel 28, a zoom lens frame 29, a focus lens frame 30, a zoom lens barrel 31, a cam ring 32, a focus lens barrel 33, and a coil spring 34. , A spring pressing ring 35. The fixed cylinder 28 is composed of a cylinder portion 28a having a penetrating inner diameter portion 36, and a pedestal portion 28b that is integrally formed with the cylinder portion 28a and is used when assembled in the main body portion 3. The front side faces the imaging opening 13 of the image input device 2, and the rear side faces the CCD 8.

On the outer peripheral surface of the cylindrical portion 28a, elongated holes 38a, 3
8b, grooves 39a and 39b, and recesses 40a and 40b,
Three claws 41 are formed. Oblong holes 38a, 38b
Are arranged side by side along the optical axis 42, and the elongated hole 38a on the rear side is longer than the elongated hole 38b on the front side. The two grooves 39a and 39b have a V-shaped cross section, and are provided along the optical axis 42 so as to sandwich the elongated hole 38b. These grooves 39a and 39b constitute a focusing mechanism that stops the focus lens barrel 33 at the focus position. The recesses 40a and 40b have an arc-shaped cross section and are used to prevent the cam ring 32 from rotating. 3
The individual claws 41 are for attaching the spring pressing ring 35 to the fixed cylinder 28.

The focus lens frame 30 holds a focus lens 44 used for focusing. Two support parts 30 are provided on the outer periphery of the focus lens frame 30.
a and 30b and a cam shaft 30c are projected. The two support portions 30a and 30b are two guide shafts 45 that are assembled along the optical axis 42 in the inner diameter portion 36 of the tubular portion 28a.
a, 45b are inserted through the focus lens frame 3
0 is movably supported along the optical axis 42. Cam shaft 30
The c is inserted into the elongated hole 38b of the tubular portion 28a.

The zoom lens frame 29 holds a zoom lens 47 used for zooming. On the outer periphery of the zoom lens frame 29, like the focus lens frame 30,
Two supporting portions 29a and 29b and a cam shaft 29c are provided in a protruding manner. Two guide shafts 45a and 45b are inserted through the two support portions 29a and 29b, and the zoom lens frame 29
Are movably supported along the optical axis 42. Cam shaft 29c
Is inserted into the elongated hole 38a of the tubular portion 28a. One end side of the two guide shafts 45 a and 45 b is supported by the rear side of the fixed cylinder 28, and the other end side is supported by the inner wall of the upper surface of the main body 3.

The zoom lens barrel 31 has a tubular portion 28 of the fixed barrel 28.
It is rotatably attached to the outer periphery of a. Zoom lens barrel 31
Includes a zoom dial 11, a cam slit 31a,
A pair of cam surfaces 31b and 31c are provided. The zoom dial 11 has a knurled groove formed on its outer peripheral surface so as to prevent slippage, and is exposed to the outside from the front surface side of the main body 3. The cam slit 31a corresponds to the zoom lens frame 29 described above.
The cam shaft 29c is inserted, and the rotation of the zoom lens barrel 31 advances and retracts the zoom lens frame 29 along the optical axis 42.

The cam surfaces 31b and 31c are the zoom lens barrel 31.
Is formed symmetrically with respect to the optical axis 42 on the end face on the front side, and has a shape in which the central portion projects toward the rear side. Then, when the zoom lens barrel 31 is rotated,
The focus lens barrel 33 is moved along the optical axis 42 via the cam ring 32 that comes into contact with the cam surfaces 31b and 31c.

The cam ring 32 has a tubular portion 2 of the fixed barrel 28.
An inner diameter portion 32a through which 8a is inserted is formed, and recesses 40a, 4 of the tubular portion 28a are formed in the upper and lower portions of this inner diameter portion 32a.
The convex portions 32b and 32c are formed so as to enter the inside of 0b. This allows the cam ring 32 to move along the optical axis 42 without rotating with respect to the fixed barrel 28. Also,
A pair of cam projections 49 is provided on the rear end surface of the cam ring 32.
a, 49b are formed. These cam projections 49
a, 49b are cam surfaces 31b, 31b of the zoom lens barrel 31 due to the bias of the coil spring 34 via the focus lens barrel 33.
Pressed against 31c. When the zoom lens barrel 31 is rotated, the optical axes 4 are pressed by the cam surfaces 31b and 31c.
Go back and forth along 2.

The focus lens barrel 33 is rotatably attached to the outer periphery of the tubular portion 28a of the fixed barrel 28. The focus lens barrel 33 includes a switching dial 10 and a cam slit 3.
3a and an opening 33b are provided. The switching dial 10 has a non-slip knurled groove formed on its outer peripheral surface, and is exposed to the outside from the front surface side of the main body 3. The cam shaft 30c of the focus lens frame 30 is inserted into the cam slit 33a, and the focus lens frame 30 is moved back and forth along the optical axis 42 by the rotation of the focus lens barrel 33.

As shown in FIG. 7, the opening 33b is formed along the rotation direction of the focus lens barrel 33,
The outer peripheral surface of the fixed cylinder 28 is exposed. A leaf spring 51 is attached by a screw 52 near the opening 33b. The leaf spring 51 is made of a thin metal plate and has a bent engaging portion 51a formed at its tip.

When the focus lens barrel 33 is rotated, the engaging portion 51a of the leaf spring 51 opens the opening 3 during the rotation.
The focus lens barrel 33 is locked by entering the groove 39a or the groove 39b of the cylindrical portion 28a through 3b. Groove 3 mentioned above
Reference numerals 9a and 39b are for a photographic film and a print photograph, respectively, and when the leaf spring 51 engages with the groove 39a, the focus lens frame 39 is inserted into the slot 15 of the head portion 6 inside the film carrier 14. When the photo film 24 is in focus and the leaf spring 51 is engaged with the groove 39b, the focus lens frame 30 is in focus on the print photo 26 between the arm portions 4 and 5.

The spring pressing ring 35 is engaged with the claw portions 41 formed on the outer peripheral surface of the tubular portion 28a at equal intervals. A coil spring 34 is housed between the spring holding ring 35 and the focus lens barrel 33, and the coil spring 34 presses the end surface of the focus lens barrel 33. As a result, the focus barrel 33 is biased toward the zoom barrel 31 side.

Next, the operation of the above embodiment will be described. When picking up an image of the developed photographic film, the arms 4 and 5 are slightly opened with respect to the main body 3 as shown in FIG. The image input device 2 is erected. Then, the image input device 2 is connected to a monitor or the like, and the film carrier 14 having the photographic film 24 sandwiched therein is inserted into the slot 15. Further, depending on the orientation of the image, the head portion 6 is rotated with respect to the main body portion 3.

When the power of the image input device 2 is turned on in the above state, the lamps 21 and 22 in the lamp houses 19 and 20 are turned on, and the photographic film 24 in the film carrier 14 is illuminated through the imaging opening 13. This photo film 2
The light illuminating 4 is imaged on the CCD 8 through the zoom lens 7. The CCD 8 photoelectrically converts the light that illuminates the photographic film 24, and outputs it as a video signal to the monitor by the image input device 2.

When the image displayed on the monitor is checked and the image is out of focus, the zoom lens 7 is in a state of taking a photograph of the print. Therefore, the switching dial 10 is used as an index to focus on the photo film. Rotate toward "F" side. Then, as shown in FIGS. 1, 3, and 6, the focus lens barrel 33 is rotated counterclockwise in the drawings,
The cam shaft 30c is pressed by the movement of the cam slit 33a. As a result, the focus lens frame 30 moves toward the photographic film 24 along the optical axis 42. When the switching dial 10 is further rotated, the leaf spring 51 engages with the groove 39a of the fixed barrel 28 as shown in FIG.

In this state, the focus lens frame 30 is in focus on the photo film 24, and the image of the photo film 24 in focus is displayed on the monitor.

When enlarging the image of the photographic film 24 to be picked up, the zoom dial 11 is rotated toward the index "T" side. Then, as shown in FIGS.
The zoom lens barrel 31 is rotated counterclockwise in the figure, the cam shaft 29c is pressed by the movement of the cam slit 31a, and the zoom lens frame 29 moves along the optical axis 42 toward the CCD 8 side.

At this time, the cam surfaces 31b, 31c
The cam protrusions 49a, 49b of the cam ring 32 are pressed by the cam ring 32, and the cam ring 32 and the focus lens barrel 33 move along the optical axis 42 against the bias of the coil spring 34 toward the imaging opening 13 side. During the movement of the focus lens barrel 33 due to the rotation of the zoom lens barrel 31, the engaging portion 51a of the leaf spring 51 is engaged with the groove 39a, and the leaf spring 51 moves in the groove 39a. The image of the photographic film 24 is enlarged and displayed on the monitor in a focused state without any misalignment.

When the image pickup range of the photographic film 24 is returned to the original, the zoom dial 10 is rotated toward the index "W" side. Then, the zoom lens barrel 31 rotates clockwise in FIG. 1, and the movement of the cam slit 31a causes the zoom lens frame 29 to move toward the focus lens 30 side. Further, since the cam ring 32 is released from the pressing force of the cam surfaces 31b and 31c by the rotation of the zoom lens barrel 31, the biasing force of the coil spring 34 causes the focus lens barrel 3 to move.
3 and the cam ring 32 move toward the zoom lens frame 29 side.

Further, when a reflection original such as a print photograph is taken, as shown in FIG. 5, the arms 4 and 5 are widely opened with respect to the main body 3, and the image input device 2 is inverted. The lamp houses 19 and 20 are opened, and the print photograph 26 is arranged between the arm portions 4 and 5.

In the above state, the power of the image input device 2 is turned on, and when the image displayed on the monitor is out of focus, the switching dial 10 is rotated toward the index "P" side. Then, as shown in FIGS. 1, 3 and 6, the focus lens barrel 33 is rotated clockwise, the cam shaft 30c is pressed by the movement of the cam slit 33a, and the focus lens frame 30 is imaged along the optical axis 42. It moves in a direction away from the opening 13. When the switching dial 10 is further rotated, the leaf spring 51 engages with the groove 39b of the fixed barrel 28.

In this state, the focus lens frame 30 is in focus on the print photograph 26, and the image of the print photograph 26 in focus is displayed on the monitor.

When the image of the print photograph 26 to be taken is reduced, the zoom dial 11 is rotated toward the index "W" side. Then, as shown in FIGS.
The zoom lens barrel 31 is rotated clockwise in the figure, the cam shaft 29c is pressed by the movement of the cam slit 31a, and the zoom lens frame 29 is moved along the optical axis 42 to the focus lens frame 3
Move toward the 0 side.

At this time, the cam surfaces 31b, 31c
The cam protrusions 49a, 49b of the cam ring 32 are pressed by the cam ring 32, and the cam ring 32 and the focus lens barrel 33 move along the optical axis 42 against the bias of the coil spring 34 toward the imaging opening 13 side. During the movement of the focus lens barrel 33 due to the rotation of the zoom lens barrel 31, the engaging portion 51a of the leaf spring 51 is engaged with the groove 39b, and the leaf spring 51 moves in the groove 39b. The image of the print photograph 26 is reduced and displayed on the monitor in a focused state without any deviation.

Although the image input device has been described as an example in the above embodiment, the zoom lens of the present invention can be used in a compact camera, a video camera, a still camera, or other optical devices. Further, although the focus lens is arranged in the front and the zoom lens is arranged in the rear, these may be arranged in reverse. Furthermore, although the number of grooves in which the leaf spring engages is two, the number of grooves is not limited to this, and it is also possible to easily focus on a large number of subjects having different focal lengths.

[0039]

As described above, according to the zoom lens of the present invention, the position of the focus lens is focused on at least two objects at different distances so that the position of the zoom lens does not shift due to the rotation of the zoom lens barrel. Since the focusing mechanism that mechanically stops the rotation of the focus lens barrel is provided, it is possible to easily focus on the subject having a specific focal length. Further, it is possible to prevent the focus from being deviated due to the zoom operation after focusing.

Also, a leaf spring having a focusing mechanism attached to the focus lens barrel and contacting the outer peripheral surface of the fixed barrel,
Since it is provided on the outer peripheral surface of the fixed barrel along the optical axis direction and has a simple structure including a groove into which a leaf spring is inserted while the focus lens barrel is rotating, it can be used at low cost.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing a configuration of a zoom lens.

FIG. 2 is an external perspective view showing a state of the image input device when not in use.

FIG. 3 is a cross-sectional view of a main part of a zoom lens incorporated in an image input device.

FIG. 4 is an external perspective view showing a state of the image input device at the time of inputting a photo film.

FIG. 5 is an external perspective view showing a state of the image input device at the time of inputting a print photograph.

FIG. 6 is an external perspective view of a zoom lens.

FIG. 7 is a cross-sectional view of a main part of a zoom lens.

[Explanation of symbols]

 2 image input device 3 main body part 6 head part 7 zoom lens 8 CCD 10 switching dial 11 zoom dial 13 imaging aperture 28 fixed barrel 29 zoom lens frame 30 focus lens frame 31 zoom barrel 32 cam ring 33 focus barrel 34 coil spring 35 spring retainer Ring 39a, 39b Groove 51 Leaf spring

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ryuta Sasaki 1-324 Uetakecho, Omiya City, Saitama Prefecture Fuji Photonics Co., Ltd.

Claims (2)

[Claims] 1. A fixed barrel for holding a focus lens and a zoom lens movably along the optical axis direction, and a fixed barrel rotatably mounted on the outer periphery of the fixed barrel to move the focus lens along the optical axis direction. In a zoom lens including a focus lens barrel and a zoom lens barrel that moves the zoom lens and the focus lens barrel along the optical axis direction, at a position where the focus lens is focused on at least two or more different distance subjects. A zoom lens comprising a focusing mechanism for mechanically stopping rotation of the focus lens barrel so that the position of the zoom lens barrel does not shift due to rotation of the zoom lens barrel. 2. The focus mechanism is attached to the focus lens barrel, and is provided on the outer peripheral surface of the fixed barrel along the optical axis direction. The zoom lens according to claim 1, wherein the zoom lens comprises a groove into which a leaf spring enters during rotation.