JPH08184739A - Lens barrel - Google Patents

Abstract

PURPOSE: To cope with miniaturization and/or thinning by attaching a housing in which a fixed lens group is held to a chassis so as to cover the one surface of the chassis and housing an internal mechanism in the housing. CONSTITUTION: The housing 2 in which the front fixed lens group 3 is held at a front end 2e is attached to the chassis 4 to which the internal mechanism 5 is attached so as to cover the internal mechanism 5, and coupled by screwing. Thus, a guide shaft and a nut for zooming, a nut for focusing and a position sensor supported by the guide shaft are housed in the main part 2a of the housing 2, and a lens group 6, an iris case, an iris blade and a moving frame are housed in the main part 2a and a lens housing part, then an iris motor 40 is housed in an iris motor housing part 2d. A CCD is mounted in a mount hole formed in the recessed part of the back wall of the housing 2. In such a case, the housing 2 has shape corresponding to the shape of the mechanism 5 attached to the chassis 4 and needless space is not formed in the housing 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel lens barrel. For details, reduce the number of parts and improve assembly workability,
Furthermore, it is possible to contribute to cost reduction by improving the assembling accuracy of each component, and to provide a novel lens barrel that can be downsized and / or thinned. It is what

[0002]

2. Description of the Related Art For example, a lens system such as a zoom movable lens group and a focus movable lens group as an internal mechanism of a video camera, a zoom lens drive mechanism for driving the zoom movable lens group, and a focus movable lens group. There is provided a focus lens drive mechanism and the like for driving, and these are integrated to form a lens barrel.

FIG. 9 shows an example a of such a conventional lens barrel.

Reference numeral b denotes a substantially cylindrical housing, and a front half c forming a front half portion thereof and a rear half d forming a rear half portion thereof.
And are integrally connected.

The front half c has a fixed lens group e held internally at the front end thereof, and the zoom movable lens group g held internally by the moving frame f is positioned behind the fixed lens group e.
The moving frame f is slidably supported by two guide shafts h and i which are vertically separated from each other.

An iris j is fixed to the front end of the rear half d, and a fixed lens group 1 held internally in a fixed frame k that is in contact with the iris j is located on the rear side of the rear half d. Further, the focus movable lens group n retained in the movable frame m in an inwardly-fitted state is located further behind it. Moving frame m
Is slidably supported by two guide shafts o and p vertically separated from each other.

Reference numerals q and r denote a zoom motor and a focus motor, respectively, which are supported by frames s and t partially protruding outside the casing b and are attached to the casing b.

Further, u is an iris motor for driving the iris j mounted on the outer peripheral surface of the upper surface of the rear half d,
v is a CCD attached to the rear end.

[0009]

By the way, in the above-mentioned lens barrel a, each member attached to the front half c and each member attached to the rear half d are assembled. Separately, and then attached to the front half c in order to integrally form the front half c forming the front half of the housing b and the rear half d forming the rear half to form the lens barrel a. There is a tendency for a positional deviation between each of the mounted members and each member attached to the rear half d, and the assembly work for preventing the positional deviation is not easy. Further, since the respective moving frames f and m are separately assembled in the front half c and the rear half d, two guide shafts are required for each four, so that the number of parts is large and the cost is high. Furthermore, since a part of the frames s and t to which the motors q and r are attached and the iris motor u are located outside the housing b, the lens barrel a has a complicated shape with irregularities, which makes it bulky. Therefore, there is also a problem that it is difficult to cope with recent downsizing and / or thinning of video cameras and the like.

[0010]

Therefore, in order to solve the above-mentioned problems, the lens barrel of the present invention has an internal mechanism of the lens barrel mounted on one surface of a substantially plate-shaped chassis by a required assembly method. A housing having the front fixed lens group held at the front end is attached to the chassis so as to cover one surface thereof, and the internal mechanism is housed in the housing.

[0011]

Therefore, in the lens barrel of the present invention, the assembling work is simple, the assembling accuracy of each member into the housing is improved, and the number of parts is small, which contributes to the cost reduction. I can. Further, since each member forming the internal mechanism of the lens barrel is housed in the housing, the external shape is not complicated and it is possible to cope with recent downsizing and / or thinning of video cameras and the like. It becomes easier to handle and the production efficiency can be improved.

[0012]

The details of the lens barrel of the present invention will be described below with reference to an example of embodiment shown in the drawings.

Reference numeral 1 is a lens barrel.

Reference numeral 2 denotes a housing made of synthetic resin, the shape of which will be described below.

The main portion 2a of the housing 2 is long in the front-rear direction and is formed in a substantially semi-elliptical shape with a cross-sectional shape. Reference numerals 2b and 2c respectively denote a substantially semi-cylindrical lens housing portion and a rear end portion integrally provided on the right side of the main portion 2a, and the lens housing portion 2b is located at a position approximately 3/4 of the front end of the main portion 2a. The rear end portion 2c, which has a smaller diameter than the lens storage portion 2b, is provided up to the rear end of the main portion 2a, following the lens storage portion 2b. Reference numeral 2d denotes an iris motor storage portion that is integrally provided from the lens storage portion 2b and has a substantially quarter arc shape in a cross-sectional shape, and is located diagonally below and to the right of the rear end of the lens storage portion 2b. Reference numeral 2e denotes a front end portion which is integrally provided in front of the lens housing portion 2b and has a short cylindrical shape in the front-rear direction. The rear half of the front end 2e has the same diameter as the lens housing 2b, and the front half has a diameter slightly larger than that of the latter half. A recess 2f is formed on the rear wall of the housing 2, and a mounting hole 2g for mounting a CCD, which will be described later, is formed on the bottom surface of the recess 2f.

Therefore, the housing 2 has a shape which is open on the left side except for the front end portion 2e. Further, cutouts 2h and 2h cut out toward the opening side are provided above and below the rear end of the main portion 2a.
Are formed.

Reference numeral 3 denotes a front fixed lens group, which is used for the housing 2
It is retained in the front end portion 2e by heat caulking in an in-fit state.

4 is a chassis having a substantially rectangular plate shape,
On one surface of the chassis 4, mounting members for mounting respective members that form an internal mechanism 5 such as a lens group and a driving mechanism thereof described later are provided. Further, notches 4a and 4b are formed above and below the rear end of the chassis 4.

Reference numeral 6 denotes a zoom movable lens group, which is internally held by thermal caulking on a main portion 8 having a short cylindrical shape in the front-rear direction of a zoom movable frame 7. A bearing portion 9 that is short in the front-rear direction is provided below the main portion 8, and a bearing hole 9a is formed in the bearing portion 9. A bearing portion 10 which is long in the front-rear direction is provided above the main portion 8, and a U-shaped groove 10a having a U-shaped cross section is formed in the bearing portion 10.

Reference numerals 11 and 12 denote guide shafts which are mounted parallel to the mounting surface of the chassis 4 at positions vertically separated from each other on the chassis 4. The guide shaft 11 is slidably inserted into the bearing hole 9a of the bearing portion 9.

Reference numeral 13 denotes a zoom driving motor for driving the zoom movable lens group 6 located above the rear end portion of the chassis 4. A ball screw 14 is connected and fixed to the rotary shaft of the zoom driving motor. The length extends to the front end of No. 4. Then, the zoom drive motor 13
The flange part 1 for mounting to the chassis 4 is at the front end of the
3a is integrally provided, and a ball screw 1 is further provided on the front side thereof.
A boss portion 13b having a diameter slightly larger than 4 is provided.

Reference numeral 15 is a zoom nut, and the nut portion 1
6 is screwed into the ball screw 14. Nut part 1
The guide shaft 12 is slidably inserted into a bearing hole 17a of a bearing portion 17 that is vertically provided. The bearing portion 17 of the zoom nut 15 is located in the U-shaped groove 10a of the bearing portion 10 of the zoom moving frame 7 and is connected to the bearing portion 10 by means not shown.

Reference numeral 18 denotes a focus movable lens group, which is located behind the zoom movable lens group 6 and is internally fitted by thermal caulking to a main portion 20 having a short cylindrical shape in the front-rear direction of the focus moving frame 19. Is held. A bearing portion 21 short in the front-rear direction is provided above the main portion 20, and a bearing hole 21a is formed in the bearing portion 21.
The guide shaft 12 is slidably inserted in a. A bearing portion 22 that is long in the front-rear direction is provided below the main portion 20, and the bearing portion 22 has a U-shaped cross section and an inverted U-shape.
The groove 22a is formed.

Reference numeral 23 denotes a focus driving motor for driving the focus movable lens group 18 located below the rear end of the chassis 4, and a ball screw 24 is connected and fixed to the rotary shaft of the focus driving motor. Ball screw 1
It is shorter than 4. A flange portion 23a for attachment to the chassis 4 is integrally provided at the front end portion of the focus driving motor 23, and a boss portion 23b having a diameter slightly larger than that of the ball screw 24 is provided on the front side thereof.

Reference numeral 25 is a focusing nut, and a nut portion 26 is screwed into the ball screw 24. The guide shaft 11 is slidably inserted into a bearing hole 27a of a bearing portion 27 provided upright from the nut portion 26. The bearing portion 27 of the focus nut 25 is located in the U-shaped groove 22a of the bearing portion 22 of the focus moving frame 19 and is connected to the bearing portion 22 by means not shown.

The zoom moving frame 7 and the focus moving frame 19 are slidably supported by the guide shafts 11 and 12.

Reference numeral 28 is a front upper portion of the chassis 4, 29 is a lower portion of the chassis 4, which is a thrust receiving member integrally projecting from the mounting surface of the chassis 4 at a position approximately one third of the front end of the chassis width. Thrust receivers 28 and 29 are provided with thrust receivers (not shown). Further, a holding wall 30, which is integrally provided directly below the thrust receiving member 28 and below the thrust receiving member 28, integrally projects from the mounting surface of the chassis 4.
31 is provided.

Reference numeral 32 denotes a frame extending integrally from the mounting surface of the chassis 4 at the front edge of the notch 4a to a portion below the notch 4a. The upper part of the frame 32 is substantially U-shaped at the center thereof. The notch 32a is formed.

Reference numeral 33 denotes a frame extending from the mounting surface of the chassis 4 at the front edge of the notch 4b to a portion above the notch 4b. The frame 33 has a substantially inverted U-shape at the lower center thereof. -Shaped notch 33a is formed.

Reference numeral 34 is an iris case, and an iris blade (not shown) is held by a substantially cylindrical shape 34a which is short in the front-rear direction. And the main part 3 of the iris case 34
A cylindrical lens holding frame 34b, which is short in the front-rear direction and has a smaller diameter than the main portion 34a, is integrally provided on the rear surface of 4a, and the rear fixed lens group 35 is internally fitted to the lens holding frame 34b by thermal caulking. Held in. Also, the main portion 34
Positioning bosses 36 and 37 are provided on both left and right side surfaces of the outer periphery of a.
Is protruding. Further, the notch 3 is formed on the outer periphery of the main portion 34a.
4c and 34c are formed so as not to interfere with the sliding of the bearing portion 10 of the zoom moving frame 7 and the bearing portion 22 of the focusing moving frame 19 with respect to the guide shafts 11 and 12. By forming the notches 34c and 34c, the storage space in the housing 2 can be reduced, which contributes to downsizing and thinning of the lens barrel 1.

On the chassis 4, the zoom movable lens group 6, the iris blades, and the rear fixed lens group 3 are arranged from the front side.
5 and the focus movable lens group 18 are attached so that their centers are arranged on the optical axis.

Reference numeral 38 denotes the boss 3 at the substantially central portion of the chassis 4.
6 is a positioning hole formed in substantially the same size as the outer shape of 6, and 39 is a positioning hole formed in the substantially central portion of the housing 2 in substantially the same size as the outer shape of the boss 37.

Reference numeral 40 denotes an iris motor, which is located behind the lower part of the iris case 34.

Reference numerals 41 and 42 denote position sensors, 41 functioning as a zoom position detecting means and 42 functioning as a focus position detecting means.

A method of assembling each member constituting the internal mechanism 5 to the chassis 4 will be briefly described below.

The zoom moving frame 7 holding the zoom movable lens group 6 is connected to the zoom nut 15, and is supported by the guide shafts 11 and 12 in this state. Similarly, the focus moving frame 19 holding the focus moving lens group 18 is coupled to the focus nut 25 and is supported by the guide shafts 11 and 12 in that state.

The guide shaft 12 is parallel to the mounting surface of the chassis 4 by press fitting between the holding wall 30 and the lower part of the frame 32 and the guide shaft 11 between the holding wall 31 and the upper part of the frame 33. It is supported in the form of a bridge.

However, both the zoom moving frame 7 and the focus moving frame 19 have the same two guide shafts 11 and 1.
Since it is slidably supported with respect to 2, the number of parts can be reduced by commonizing the parts, and further, the storage space in the lens barrel can be reduced. It is also possible to make the lens barrel smaller and / or thinner.

Assembling of the zoom moving frame 7 and the focus moving frame 19 to the chassis 4 is performed by the guide shafts 11 and 12.
Is performed by assembling in parallel with the mounting surface of the chassis 4, that is, parallel to the optical axis, so that the deviation of the optical axis between the movable lens groups 6 and 18 held by the moving frames 7 and 19 can be eliminated. .

In the iris case 34, the iris blades held by the iris case 34, and the rear fixed lens group 35, the boss 36 provided in the iris case 34 has a positioning hole 3 in the chassis 4.
8, and the boss 37 is fitted and fixed in the positioning hole 39 provided in the housing 2 when the housing 2 is joined to the chassis 4.

Since the iris case 34, the iris blade held by the iris case, and the rear fixed lens group 35 are attached only by fitting the bosses 36 and 37 into the positioning holes 38 and 39, the assembling work is performed. It is simple and the assembly time can be shortened. In addition, the rear fixed lens group 3
Since 5 is held by the lens holding frame 34b of the iris case 34, it is not necessary to hold the iris blade and the rear fixed lens group 35 by separate members, respectively, and parts are made common.

The iris motor 40 is an iris case 34.
It is arranged at a lower part of the rear of the base by means not shown.

The zoom driving motor 13 has a ball screw 14
With the tip of the abutment against the thrust bearing of the thrust bearing member 28, the notch 32a of the frame 32 is screwed while the ball screw 14 is screwed into the nut portion 16 of the zoom nut 15 previously supported by the guide shaft 12. The boss portion 13b of the zoom driving motor 13 is fitted in from above. Then, the flange portion 13a provided on the front surface of the zoom drive motor 13 is screwed to the frame 32 so that the chassis 4
Be attached to.

In the focus driving motor 23, with the tip of the ball screw 24 abutted on the thrust bearing of the thrust bearing member 29, the nut portion 26 of the focusing nut 25 previously supported by the guide shaft 11 with the ball screw 24. The boss portion 23b of the focus driving motor 23 is fitted into the notch 33a of the frame 33 from the lower side while being screwed into. Then, the flange portion 23a provided on the front surface of the focus driving motor 23 is screwed to the frame 33 and attached to the chassis 4.

The zoom drive motor 13 and the focus drive motor 23 are located in the portions of the chassis 4 where the cutouts 4a and 4b are formed. 23 is in a state of slightly protruding to the side opposite to the mounting surface of the chassis 4.

By the way, the ball screws 14 and 24 are rotated by the outputs from the zoom driving motor 13 and the focus driving motor 23, and the zoom moving frame 7 and the focusing moving frame 19 slide on the guide shafts 11 and 12. There is rattling and vibration when the thrust receiving member 2
Since the 8, 29, the holding walls 30, 31 and the frames 32, 33 are integrally provided on the chassis 4, compared to the case where the motors 13, 23, etc. are held by using a frame or the like which is a separate member, the above rattling is caused. And vibration can be suppressed.

The position sensors 41 and 42 are attached to predetermined positions of the chassis 4 by means not shown.

Then, the internal mechanism 5 to the chassis 4 is
Since the assembling of each member constituting the above can be performed from one surface of the chassis 4, that is, the mounting surface side of each member, the assembling work is easy and at the same time the assembling accuracy is improved, and Can also shorten the assembly time.

Next, a method of assembling the lens barrel 1 will be described (see FIG. 8).

The housing 2 in which the front fixed lens group 3 is held at the front end 2e is the chassis 4 to which the internal mechanism 5 is attached.
It is attached so as to cover the internal mechanism 5 and is joined by screwing. As a result, the guide shafts 11 and 12 and the zoom nut 1 supported by the guide shafts 11 and 12 are provided in the main portion 2a of the housing 2.
5, focus nut 25 and position sensor 41, 4
2 includes a lens group 6 in the main portion 2a and the lens housing portion 2b,
18, 35, the iris case 34, the iris blades, the moving frames 7, 19, and the iris motor 40 is housed in the iris motor housing 2d. CCD4
3 is a mounting hole 2g formed in the recess 2f of the rear wall of the housing 2.
Be attached to.

Therefore, the housing 2 has a shape corresponding to the shape of the internal mechanism 5 attached to the chassis 4,
Since a wasteful space cannot be formed in the housing 2, the lens barrel can be made smaller and thinner.

The substantially rectangular flat plate-shaped circuit board 44 is provided on the side opposite to the mounting surface of the internal mechanism 5 of the chassis 4, that is, the housing 2.
The cutouts 2h and 2h formed in are fitted and positioned and attached. When the circuit board 44 is attached, the motor 1
The lens barrel 1 is formed by connecting 3, 23, and 40 to a connector (not shown) provided on the circuit board 44.

[0053]

As is apparent from the above description, in the lens barrel of the present invention, the internal mechanism of the lens barrel is attached to one surface of the substantially plate-shaped chassis by a required assembling method. A housing in which a front fixed lens group is held at the front end is attached to the chassis so as to cover one surface thereof, and the internal mechanism is housed in the housing.

Therefore, in the lens barrel of the present invention, the assembling work is simple and the assembling accuracy of each member in the housing is improved,
Since the number of parts is small, it is possible to contribute to cost reduction. Further, since each member forming the internal mechanism of the lens barrel is housed in the housing, the external shape is not complicated and it is possible to cope with recent downsizing and / or thinning of video cameras and the like. It becomes easier to handle and the production efficiency can be improved.

It should be noted that the specific shapes and structures of the respective parts shown in the above-mentioned embodiments are merely examples of the implementation of the present invention, and the technical scope of the present invention is limited by these. Should not be construed in the open.

[Brief description of drawings]

1 to 8 show an example of an embodiment of a lens barrel of the present invention, which is a perspective view.

FIG. 2 is a front view.

FIG. 3 is a side view seen from the chassis side.

FIG. 4 is a rear view.

FIG. 5 is a sectional view taken along the line VV of FIG. 3;

6 is a sectional view taken along line VI-VI in FIG.

FIG. 7 is a side view showing a state in which an internal mechanism is attached to the chassis with a part cut away.

FIG. 8 is a front view showing an assembling method.

FIG. 9 is a vertical sectional view showing an example of a conventional lens barrel.

[Explanation of symbols]

 1 lens barrel 2 housing 2e front end 3 front fixed lens group 4 chassis 5 internal mechanism 7 zoom moving frame 11, 12 guide shaft 13 zoom drive motor 19 focus moving frame 23 focus drive motor 28, 29 thrust receiver Member (mounting member) 32, 33 Frame (mounting member) 34 Iris case 34c Notch 35 Rear fixed lens group 36, 37 Boss 38, 39 Positioning hole 44 Circuit board

Claims (7)

[Claims] 1. An internal mechanism of a lens barrel is attached to one surface of a substantially plate-shaped chassis by a required assembling method,
A lens barrel characterized in that a housing holding a front fixed lens group at a front end is attached to the chassis so as to cover one surface thereof, and the internal mechanism is housed in the housing. . 2. The lens barrel according to claim 1, wherein the circuit board is attached to the housing from the side opposite to the one surface of the chassis. 3. A guide shaft for the zoom moving frame and the focus moving frame is slidably supported by two guide shafts that are vertically spaced apart from each other. The lens barrel according to claim 1 or 2, which is common. 4. The lens barrel according to claim 1, wherein the rear fixed lens group is held by an iris case. 5. Two bosses are provided at opposite positions on the side surface of the iris case, one of the bosses is fitted into a positioning hole formed in the chassis, and the other is fitted into a positioning hole formed in the housing. The lens barrel according to claim 1, claim 2, claim 3, or claim 4, wherein an iris case is fixed in the housing. 6. The mounting member for mounting the zoom driving motor and the focus driving motor is integrally provided on the chassis, claim 1, claim 2, claim 3, claim 4. Alternatively, the lens barrel according to claim 5. 7. The lens barrel according to claim 4, wherein a notch is formed on the outer circumference of the iris case.