JPH08248283A - Lens barrel - Google Patents

Abstract

PURPOSE: To provide a lens barrel capable of improving workability of combining and assembling a rear lens barrel with a main barrel. CONSTITUTION: This lens barrel is provided with the main lens barrel 14 having an aperture part 14D and an axis leading guide part 14C having a cross section of a funnel-shape formed in a guide axis hole 14B, a rear lens barrel 15 combined with the main lens barrel 14, a 2nd lens group 17 arranged on the inside of the combined main lens barrel 14 and the rear lens barrel 15, a 2nd lens group holder 21 holding a 2nd lens group 17 and operated to move in an optical axis direction, and a zooming reference axis 26 and a zooming guide axis 27 movably supporting the holder 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens barrel mounted on, for example, a video camera, and more particularly, a lens mirror having a reference shaft and a guide shaft for movably supporting a movable lens in the optical axis direction. Regarding the cylinder.

[0002]

2. Description of the Related Art For example, a video camera is equipped with an autofocus mechanism for automatically focusing on a subject and an electric zoom mechanism for changing the magnification.
The autofocus mechanism and the electric zoom mechanism are achieved by a lens barrel including a focus lens and a zoom lens, which are moved in the optical axis direction by driving means inside the barrel.

A conventional lens barrel is generally provided in order of a main lens barrel, a rear lens barrel to be combined with the main lens barrel, and the insides of the main lens barrel and the rear lens barrel so that their optical axes coincide with each other. First lens group, second lens group, iris unit, third lens group, fourth lens group, second lens group holder that holds the second lens group, and third lens An intermediate frame for holding the group, and a fourth frame for holding the fourth lens group
And a lens group holder of. Further, in this lens barrel, a zoom reference shaft and a zoom guide shaft that support the second lens group holder slidably in the optical axis direction, and a fourth lens group holder are slidably movable in the optical axis direction. It comprises a reference axis for focus and a guide axis for focus which are supported by a photo sensor for detecting the moving position of the second lens group holder.

In the lens barrel constructed as described above, the second lens group holder for holding the second lens group, which is a so-called zoom lens, is driven by the driving means along the zoom reference axis and the zoom guide axis. And slides in the optical axis direction to perform zooming. Further, in the lens barrel, a fourth lens group holder that holds a fourth lens group, which is a so-called focus lens, is slid in the optical axis direction by the driving means along the focusing reference axis and the focusing guide axis. And focus operation.

[0005]

By the way, the lens barrel is assembled by combining the rear barrel with the main barrel. As shown in FIG. 4, the main barrel 55 has a zoom reference shaft 53 and a zoom guide shaft 53 that are parallel to the optical axis direction on the inner wall adjacent to the lens holding portion 55A that holds the first lens group 51. A shaft hole 56 for supporting one end of 53 is provided.

When a rear lens barrel (not shown) is mounted on the main lens barrel 55, the lens barrel is a zoom reference shaft which is previously mounted on and supported by a shaft hole 56 provided in the main lens barrel 55. 53 and one end of the zoom guide shaft 53 are inserted and combined.

However, the lens barrel is the main barrel 55.
When inserting the zoom reference shaft 53 and the zoom guide shaft 53 supported by the rear lens barrel into the respective shaft holes 56, the shaft hole 56 of the main lens barrel 55 is positioned so as to be blocked by the lens holding portion 55A or the like. Therefore, the shaft hole 56 cannot be visually confirmed.
Therefore, the lens barrel has a problem that it is difficult to assemble the main lens barrel 55 by combining the rear lens barrel.

In the lens barrel, when the rear lens barrel is combined with the main lens barrel 55, one end of the zoom reference shaft 53 and the zoom guide shaft 53 has a shaft hole 56 in the main lens barrel 55.
There was a problem that the edge of the shaft hole was abutted and damaged.

Therefore, an object of the present invention is to provide a lens barrel which makes it possible to improve the workability of assembling the rear lens barrel in combination with the main lens barrel.

[0010]

To achieve the above object, in the lens barrel according to the present invention, an opening is formed in the main barrel so that the position of one axial hole into which the reference axis is inserted can be visually confirmed. At the same time, a shaft-introducing guide portion having a funnel-shaped cross section with a diameter slightly larger than the diameter of the guide shaft is formed in the other shaft hole into which one end of the guide shaft is inserted.

[0011]

In the lens barrel according to the present invention configured as described above, when the rear lens barrel is assembled with the main lens barrel, one end portion of the guide shaft supported by the rear lens barrel has the main lens barrel. It is abutted against a shaft-introducing guide portion having a funnel-shaped cross section. Then, one end portion of the guide shaft slides along the inner peripheral portion of the shaft inviting guide portion and is inserted into the shaft hole.

[0012]

EXAMPLES Specific examples of the present invention will be described below. Example lens barrel 1 equipped with an autofocus mechanism mounted on a video camera for automatically focusing on a subject and an electric zoom mechanism for changing magnification 1 to FIG.
Will be described with reference to. The lens barrel 1 includes a main lens barrel 14
And a rear lens barrel 15 combined with the main lens barrel 14,
A first lens group 16, a second lens group 17, an iris unit 30, and a third lens group 18, which are provided in order inside the main lens barrel 14 and the rear lens barrel 15 so that their optical axes coincide with each other, The fourth lens group 19 and the second lens group 17
And a second lens group holder 21 for holding the third lens group 18, an intermediate frame 24 for holding the third lens group 18, and a fourth lens group holder 25 for holding the fourth lens group 19. .

The lens barrel 1 further includes a zoom reference shaft 26 and a zoom guide shaft 27, which support the second lens group holder 21 slidably in the optical axis direction.
And a focusing guide shaft 28 for slidably supporting the second lens group holder 25 in the optical axis direction, and a photo sensor 31 for detecting the moving position of the second lens group holder 21. To be done.

The main lens barrel 14 is formed in a cylindrical shape,
The first lens group 16 is held and fixed in one opening. The main lens barrel 14 has a first lens group 16
A reference shaft hole 14A and a guide shaft hole 14B are provided at positions opposite to each other on the outer peripheral portion of the optical axis direction, respectively. The reference shaft hole 14A and the guide shaft hole 14B,
One ends of the zoom reference shaft 26 and the zoom guide shaft 27 are inserted and supported respectively.

Further, in the guide shaft hole 14B provided in the main barrel 14, as shown in FIG. 3, the zoom guide shaft 2 is provided.
A shaft-introducing guide portion 14C having a funnel-shaped cross section with a diameter larger than the diameter of 7 is integrally formed with the center lines aligned.

As shown in FIG. 2, the main lens barrel 14 is provided with a substantially rectangular opening 14D on one side surface parallel to the zoom reference axis 26. A stepping motor 34 for slidingly moving the second lens group holder 21 is provided in the opening 14D of the main lens barrel 14.

The stepping motor 34 is supported by a bracket member 35 and is connected to the rotary shaft 34A by a connecting piece 3.
4B is supported. The connecting piece 34B is connected to the second lens group holder 21, and is rotated by driving the rotation shaft 34A of the stepping motor 34 to move via a guide shaft (not shown) provided in parallel with the rotation shaft 34A. To be done. Then, the opening 14D of the main lens barrel 14
Is closed by the provision of the bracket member 35.

The rear lens barrel 15 is formed in a rectangular tube shape, and the CCD solid-state image pickup device 33 is provided in a state where one opening is closed. The rear lens barrel 15 includes the main lens barrel 1
The reference shaft hole 15A and the guide shaft hole 15B are respectively provided in the opposite corners of the opening edge portion combined with No. 4 in parallel with the optical axis direction, and the reference shaft hole 15A and the guide shaft hole 15B are zoomed. One ends of the reference shaft 26 for zooming and the guide shaft 27 for zooming are inserted and supported respectively.

Further, inside the rear lens barrel 15, a reference shaft hole 15C and a guide shaft hole 15D are provided at opposite corners of the outer peripheral portion of the CCD solid-state image pickup device 33 in parallel with the optical axis direction. One ends of the focusing reference shaft 28 and the focusing guide shaft 29 are inserted into and supported by the reference shaft hole 15C and the guide shaft hole 15D, respectively. Further, the rear lens barrel 15 is provided with an MR sensor for detecting the moving position of the fourth lens group holder 25.

The second lens group 17 is a so-called zoom lens, and is held on the inner peripheral portion of a cylindrical second lens group holder 21. The second lens group holder 21 has a reference shaft support portion 21A and a guide shaft support portion 21B on the outer peripheral portion.
And are respectively provided integrally.

In the second lens group holder 21, the zoom reference shaft 26 is inserted into the reference shaft support portion 21A so as to be slidable, and the zoom guide shaft 27 is inserted into the guide shaft support portion 21B. It is slidably supported. Further, the second lens group holder 21 is
A position detection plate 21C facing the photo sensor 31 is integrally provided adjacent to the reference shaft support portion 21A in parallel with the zoom reference shaft 26.

Further, the second lens group holder 21
Is connected to a connecting piece 34B that is movably provided on a rotating shaft 34A of the stepping motor 34. When the stepping motor 34 is driven to rotate, the connecting piece 34B is connected.
Through the zoom reference shaft 26 and the zoom guide shaft 27.
Is slid along the optical axis.

The iris unit 30 is provided with a diaphragm hole at the center and a plurality of diaphragm blades for opening and closing the diaphragm hole. This iris unit 30 has a second
It is located between the third lens group 17 and the third lens group 17, and is supported by the intermediate frame 24 with its aperture hole aligned with the optical axis. Then, the iris unit 30 includes the rear lens barrel 15
Is connected to an iris meter 30A provided on the outer periphery of the iris meter, and the iris meter 30A drives the iris blade to open and close the iris hole. Of course, the iris unit 30 may be composed of, for example, a diaphragm device using an electrochromic element.

The intermediate frame 24 is formed in a disc shape,
The third lens group 18 is held at the center. In the intermediate frame 24, the reference shaft hole 2 is formed in the outer peripheral portion of the third lens group 18.
4A and a guide shaft hole 24B are provided respectively.
In the intermediate frame 24, one end of the focusing reference shaft 28 is inserted into and supported by the reference shaft hole 24A,
One end of the focusing guide shaft 29 is inserted into and supported by the guide shaft hole 24B.

The fourth lens group 19 is a so-called focus lens and is held on the inner peripheral portion of a cylindrical fourth lens group holder 25. Fourth lens group holder 25
The first reference shaft support portion 25A and the second reference shaft support portion 25B are integrally provided on the outer peripheral portion, and the guide shaft support portion 25C is integrally provided on the outer peripheral portion.

In the fourth lens group holder 25, the first reference shaft support portion 25A and the second reference shaft support portion 25B are slidably supported by the focus reference shaft 28, and the focus lens is also used for focus. A guide shaft support portion 25C is slidably supported on the guide shaft 29.

A coil (not shown) is integrally formed on the outer peripheral portion of the fourth lens group holder 25, and a yoke and a magnet (not shown) are arranged corresponding to the coil. Therefore, the fourth lens group holder 2
Reference numeral 5 slides in the optical axis direction along the focusing reference shaft 28 and the focusing guide shaft 29 due to the electromagnetic force generated by the current supplied to the coil.

The zoom reference shaft 26 and the zoom guide shaft 27 are supported in parallel with the optical axis at one end thereof in a reference shaft hole 15A and a guide shaft hole 15B provided in the rear lens barrel 15, respectively. The other end is supported by a reference shaft hole 14A and a guide shaft hole 14B provided in the main lens barrel 14, respectively.

Further, in order to ensure good slidability when the second lens group holder 21 slides and zooms on the zoom reference shaft 26 and the zoom guide shaft 27, for example, grease or the like is used. A relatively high viscosity lubricant is applied. That is, the zoom reference shaft 26 and the zoom guide shaft 27 are filled with a lubricant in the gap between the reference shaft support portion 21A and the guide shaft support portion 21B of the second lens holder 21, and the second lens group. Vibration accompanying the sliding of the holder 21 is reduced. Further, the zoom reference shaft 26 and the zoom guide shaft 27 have the same diameter dimension and length dimension, and the parts are commonly used.

The reference shaft 28 for focus and the guide shaft 29 for focus are parallel to the optical axis, and one end of the reference shaft hole 24A and the guide shaft hole 24B are provided in the intermediate frame 24.
And the other end is supported by a reference shaft hole 15C and a guide shaft hole 15D provided in the rear lens barrel 15, respectively.

In order to ensure good slidability when the fourth lens group holder 25 slides and performs a focus operation on the focusing reference shaft 28 and the focusing guide shaft 29, for example, a fluorine system is used. A lubricant having a relatively low viscosity such as oil is uniformly applied. That is, the focus reference axis 28 and the focus guide axis 29
Since the fourth lens holder 24 slides at a relatively high speed, the lubricant having a relatively low viscosity ensures good slidability.

The photo sensor 31 is provided with a light emitting portion for emitting the detection light and a light receiving portion for receiving the detection light, and is arranged at one end side of the zoom reference shaft 26. Then, in this photo sensor 31, the position detection plate 21C provided in the second lens group holder 21 blocks the infrared light emitted from the light emitting unit, and the light amount received by the light receiving unit is changed and output. The voltage changes. Photo sensor 31
Changes depending on the output voltage of the second lens group holder 2
The moving position of 1 is detected.

The central portion of the moving range of the second lens group holder 21 that slides along the zoom reference shaft 26 and the zoom guide shaft 27 is the reference position (reset position). ing. In the photo sensor 31, the second lens group holder 21 has the zoom reference axis 2
6 and the slide guide shaft 27 toward the rear lens barrel 15 side, the position detection plate 21C of the second lens group holder 21 detects the infrared light emitted from the light emitting unit at the reset position. Block. Therefore, the photo sensor 31
It is detected that the second lens group holder 21 is located at the reset position.

The lens barrel 1 constructed as described above is
The second lens group holder 21 that holds the second lens group 17 with respect to the fixed first lens group 16 is provided with an optical axis along the zoom reference axis 26 and the zoom guide axis 27 by the stepping motor 34. It slides in the direction and zooms.

In the lens barrel 1, the fourth lens group holder 25, which holds the fourth lens group 19 with respect to the fixed third lens group 18, uses the electromagnetic force generated in the coil as a reference for focusing. The axis 28 and the focusing guide axis 29 are slid in the optical axis direction to perform the focusing operation.

Regarding the lens barrel 1 described above, the main barrel 1
The operation of assembling the rear lens barrel 15 in combination with No. 4 will be described. The lens barrel 1 is a reference shaft hole 1 of the main lens barrel 14.
The zoom reference shaft 26 and the zoom guide shaft 27 whose one end is cantilevered in advance by the rear lens barrel 15 are inserted into the 4A and the guide shaft hole 14B, respectively, to be assembled.

When inserting the zoom reference shaft 26 supported by the rear barrel 15 into the reference barrel hole 14A, the main barrel 14 visually confirms the position of the reference barrel hole 14A from the opening 14D,
One end of the zoom reference shaft 26 is inserted.

When the zoom guide shaft 27 supported by the rear lens barrel 15 is inserted into the guide shaft hole 14B, the main lens barrel 14 is guided along the shaft calling guide portion 14C formed in the guide shaft hole 14B. One end of the zoom guide shaft 27 slides and is inserted into the guide shaft hole 14B. That is,
The main barrel 14 can be inserted with one end of the zoom guide shaft 27 even if the position of the guide shaft hole 14B cannot be visually confirmed.

Therefore, in the lens barrel 1, the zoom reference shaft 26 and the zoom guide shaft 27 supported by the rear lens barrel 15 with respect to the reference shaft hole 14A and the guide shaft hole 14B of the main lens barrel 14 are securely provided. It is inserted and assembled in each.

As described above, the lens barrel 1 according to the embodiment is
Since the guide portion 14C for invoking the shaft is formed in the guide shaft hole 14B of the main lens barrel 14, the guide shaft hole 14B is formed.
When inserting the zoom guide shaft 27 supported by the rear lens barrel 15, one end of the zoom guide shaft 27 slides along the shaft invoking guide portion 14C provided in the guide shaft hole 14B to slide into the guide shaft hole. It is plugged into 14B. Therefore, the lens barrel 1 has the guide shaft hole 14B of the main barrel 14.
Further, it is easy to insert the other end of the zoom guide shaft 27 whose one end is cantilevered and supported in the rear lens barrel 15.

Therefore, the lens barrel 1 is the main lens barrel 14
On the other hand, the rear lens barrel 15 can be assembled easily and surely. That is, the lens barrel 1 improves the efficiency of the assembly work.

Further, the lens barrel 1 has the opening 14D formed in the main lens barrel 14, so that when the zoom reference shaft 26 supported by the rear lens barrel 15 is inserted into the reference shaft hole 14A, the reference shaft The position of the hole 14A can be visually confirmed from the opening 14D. Therefore, in the lens barrel 1, it is easy to insert the zoom reference shaft 26 supported by the rear lens barrel 15 into the reference shaft hole 14A of the main lens barrel 14. Therefore, in the lens barrel 1, the rear lens barrel 15 can be easily and surely assembled to the main lens barrel 14,
Improves the efficiency of assembly work.

According to the lens barrel 1 of this embodiment, the opening 14D formed in the main barrel 14 is provided with the bracket member 35 supporting the stepping motor 34. It goes without saying that another member constituting the lens barrel 1 may be provided in the above.

The lens barrel 1 has a zoom reference shaft 2
6 and the zoom guide shaft 27, and the focus reference shaft 2
8 and the focusing guide shaft 29 are provided respectively, but a set of a reference shaft and a guide shaft may be provided.

[0045]

As described above, according to the lens barrel of the present invention, the main barrel is provided with the opening through which the position of the shaft hole into which the reference shaft is inserted can be visually confirmed, and the guide shaft. Work to assemble the rear lens barrel to the main lens barrel by forming a shaft-introducing guide part with a funnel-shaped cross-section with a diameter slightly larger than the diameter of the guide shaft in the other shaft hole Improve sex.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing an example lens barrel according to the present invention.

FIG. 2 is a partial cross-sectional side view showing a main lens barrel forming the lens barrel.

FIG. 3 is a longitudinal sectional view of an essential part showing a guide shaft hole of a main lens barrel forming the lens barrel.

FIG. 4 is a longitudinal sectional view of an essential part showing a shaft hole of a main lens barrel forming a conventional lens barrel.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lens barrel 14 Main barrel 14A Reference shaft hole (shaft hole) 14B Guide shaft hole (shaft hole) 14C Axis invoking guide portion 15 Rear lens barrel 17 Second lens group (movable lens) 21 Second lens group Holder (movable lens holder) 26 Zoom reference axis (reference axis) 27 Zoom guide axis (guide axis)

Claims (3)

[Claims] 1. A main lens barrel having a pair of shaft holes opened in the optical axis direction on an inner wall, and a main shaft provided with a reference shaft and a guide shaft whose one end is cantilevered in parallel with the optical axis direction. A rear lens barrel that is combined with the lens barrel, a movable lens that is disposed inside the combined main lens barrel and rear lens barrel, and a movable lens that is moved along the optical axis while holding the movable lens. The movable lens holder and one end parallel to the optical axis direction are cantilevered by the rear barrel, and the other end is inserted into the axial hole of the main barrel when the rear barrel and the main barrel are combined. The main lens barrel has a reference shaft and a guide shaft, and an opening is formed in the main lens barrel so that the position of one shaft hole into which the reference shaft is inserted can be visually confirmed, and the other shaft hole into which one end of the guide shaft is inserted. A funnel-shaped cross section with a diameter slightly larger than the diameter of the guide shaft A lens barrel, wherein a for axial attracting guide portion is formed. 2. The lens barrel according to claim 1, wherein the movable lens is a zoom lens. 3. The driving means for driving the movable lens holder parallel to the optical axis direction along the reference axis and the guide axis is provided in the opening.
The lens barrel described in.