JPH089692Y2 - Focusing device for lens barrel for optical equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a focusing device for a lens barrel for optical equipment.

[Conventional technology]

A mechanism for moving the lens barrel back and forth for focusing the optical system in the lens barrel for optical equipment (hereinafter referred to as "focusing") is called a helicoid focus adjustment mechanism, which is a multiple thread screw provided on the hollow cylindrical body. A mechanism using (hereinafter referred to as a helicoid screw) is often adopted. In particular, a hollow cylinder provided with a helicoid screw is called a helicoid cylinder, a male screw side is called a male helicoid cylinder, and a female screw side is called a female helicoid cylinder.

Generally, the female helicoid cylinder is fixed to the external operation member, and in addition to the helicoid screw screwed with the male helicoid cylinder, a small pitch to be screwed to the fixed body on the member side to be mounted on the optical device body, and , And has a screw whose screw direction is opposite to that of the helicoid screw. The male helicoid cylinder holds the optical system, is connected to the fixed body in the relationship of the linear guide key and the key groove, and by rotating the external operation member (that is, the female helicoid cylinder), the thrust force of the helicoid screw causes the male helicoid cylinder to rotate. The cylinder is pushed out and goes straight along the keyway. At this time, since the optical system is held in the male helicoid cylinder, it has the function of performing the focusing operation.This mechanism is called a straight-ahead helicoid focus adjustment mechanism, and is a lens barrel for optical equipment of intermediate or higher grade lens. Is often used in the focusing device of.

The helicoid screw of the lens barrel for optical equipment requires particularly high precision and a good feeling of operation. Therefore, in the conventional helicoid screw, screwing is performed after mechanical processing such as waring, and further lapping is performed. It has been implemented as a means to secure the above-mentioned requirements such as the degree of screwing clearance of screws and the degree of feel of screw rotation. Therefore, the helicoid cylinder is expensive to process. However, recently, especially in the lens barrel for optical equipment, it has become an essential condition to supply high-performance products to the market at an extremely low price. Traditionally, the components of the lens barrel for optical equipment were all processed with high precision using metal materials, and high-quality lens barrel was constructed by this, but plastic molding technology, mold manufacturing technology With the development of such products, plastic molded parts are actively adopted for lens barrels for optical equipment that require high performance, and processing cost, and eventually product value reduction, product weight reduction, etc. The development of products that meet the above requirements has been requested.

[Problems to be solved by the invention]

However, even if we try to obtain higher quality plastic molded parts such as the helicoid tube of the lens barrel for optical equipment, in reality, we will provide them as parts that are sufficiently satisfactory in terms of accuracy and cost. The reality is that we cannot get it.

The first reason is the problem of molding strain that occurs when molding a helicoid cylinder with a plastic material. Helicoid screws are molded on the circumference of the cylinder, and in order to eliminate the overhang of the screw part, it is necessary to remove the mold,
Alternatively, it is necessary to mold with a split mold that has at least a three-part mold configuration, and in any case, it becomes very difficult to produce molded parts with high roundness accuracy that suppress molding distortion to an extreme degree. Inevitably, the die manufacturing cost also rises, and the second problem is the cost of molded parts.

Furthermore, in the case of a product that can be expected to be produced in large numbers, even if the initial cost is high, it does not have to be a large weight, but in the case of the production of a small number of products, it is difficult to resinify it in terms of cost. It can be said that this is because of the configuration of the lens barrel component that has the above-mentioned helicoid screw. In recent years, there have been cases in which a large number of infrared LEDs are arranged in a night-vision camera or the like to take advantage of the infrared sensitivity characteristics of the CCD and the infrared illumination is used for photographing. In this case, in order to correct the amount of change in the focus position due to the difference between the focus position in the visible light range and the infrared light, it is necessary to move the infinite stop position. Incorporating the above-mentioned correction function into the focusing mechanism of (3) has complicated elements. For example, if the stopper position in the direction of rotation of the helicoid is moved by a correction amount, the shooting condition can be satisfied, but the shooting distance scale cannot be used. Therefore, since the cost is also high, the conventional correction function has not been provided.

[Means for solving problems]

The present invention has been made in view of the above-described problems, and is a fixed lens barrel 1 that is a mounting member for an optical device body, and an optical system holding member that is fitted to the fixed lens barrel through a linear guide key. In a lens barrel for optical equipment including a lens barrel 4,
An operating shaft sandwiched between the fixed lens barrel 1 and the lens barrel 4 and provided with a leaf spring 5 for constantly urging the fixed lens barrel 1 and the lens barrel 4 in the direction of approaching each other, and fitted in the lens barrel 4 so as to be movable only in the optical axis direction. 2 is provided, and the operation shaft 2 is screwed with an operation member 3 having a part protruding to the outside on the fixed lens barrel 1 side, and with a focus adjustment nut 7 screwed on the lens barrel 4 side. , One end face in the axial direction is brought into contact with the fixed lens barrel 1, and the end face of the focus adjustment nut 7 is brought into contact with the inner side wall 8a of the decorative frame 8 fixed to the lens barrel 4, whereby the fixed lens barrel is fixed. The lens barrel 4 is sandwiched between the lens barrel 1 and the lens barrel 4, and the focus adjustment nut 7 is rotated to move the lens barrel 4 in the optical axis direction to perform a focusing operation at an infinite position of the optical system. Operation member 3
By rotating the operating member 3 against the fixed lens barrel 1, the lens barrel 4 is moved in the optical axis direction against the repulsive force of the leaf spring 5 by rotating the operating member 3 to the infinite position. An object of the present invention is to provide a focusing device for a lens barrel for an optical instrument, which is characterized by performing a focusing operation in accordance with a change in shooting distance other than the above.

Further, the present invention provides the visible light correction frame 10 detachably attached to the lens barrel in the above focusing device, and by attaching the visible light correction frame 10, the focus adjustment nut 7 is The lens barrel 4 is pressed and moved to the fixed lens barrel 1 side and moved in the optical axis direction to be adjusted to the in-focus position corresponding to the wavelength range of visible light photography, and by removing the visible light correction frame 10. , The focus adjustment nut 7
Correction frame for visible light so that the pressure is released and the focus position is automatically adjusted to a position different from the visible light wavelength range.
A lens mirror for an optical device characterized in that a dimension 1 in the optical axis direction of the focus adjustment nut 7 is set based on a width dimension L of the optical axis direction 10 and a correction amount Δx relating to a focusing position in a photographing wavelength range. It is intended to provide a focusing device for a torso.

〔Example〕

An embodiment in which the present invention is applied to a lens barrel for a CCTV camera will be described below with reference to the accompanying drawings. FIG. 1 is a side sectional view of a lens barrel for a CCTV camera to which the present invention is applied, FIG. 2 is a side sectional view showing another embodiment to which the present invention is applied, and FIG. FIG.

In FIG. 1, the lens barrel includes a fixed barrel 1 mounted on a camera body (not shown), an operating shaft 2, an operating member 3, a lens barrel 4 for holding a lens group, a leaf spring 5, It is composed of a straight guide key 6 for moving the lens barrel 4 straight, a focus adjustment nut 7, a lens frame 8, a straight guide screw 9 of the operating shaft 2, and the like.

Although the illustrated lens barrel has the simplest structure and is very general, it does not directly relate to the present invention, but in order to simplify the description, the omission of the diaphragm mechanism and the integration of the composite parts are integrated. It is displayed as

The fixed lens barrel 1 is provided with a mount screw 1a for mounting on the camera body, a spigot diameter 1D for fitting with the lens barrel 4, and a guide hole 1b for the linear guide key 6. The operating shaft 2 is a lens barrel 4
The intermediate shaft portion 2a fixed to the straight guide screw 9 for the straight guide, which fits in the guide groove 4a, is fitted in the lens barrel 4 and is movable only in the axial direction without rotating with respect to the lens barrel 4. I am doing it. Screws 2b and 2c are provided at both ends of the operating shaft 2,
The operation member 3 is screwed into one screw portion 2b, and the focus adjusting nut 7 is screwed into the other screw portion 2c. The operation member 3 is screwed and coupled to the operation shaft 2 for focusing operation in a state where it is projected from the exterior member of the lens barrel to the extreme part, and is rotated to the abutting surface 1u of the fixed lens barrel 1 by rotation operation. It has an end face 3u that abuts and regulates the distance from the lens barrel 4. The focus adjustment nut 7 that is screwed into the other screw portion 2c of the operation shaft 2 is
It has a collar surface 7a that comes into contact with the inner wall 8a of the decorative frame 8 of the lens barrel 4, penetrates through the guide hole 8b of the decorative frame 8, and is near the filter mounting screw portion 8c provided in the decorative frame 8 and has a sliding slot 7b. Head with 7c
Is issued. By screwing a visible light correction frame 10 and the like, which will be described later, onto the filter mounting screw portion 8c, the end surface of the visible light correction frame 10 contacts the focus adjustment nut 7 and presses the operating shaft 2 against the fixed lens barrel 1. However, the space between the fixed lens barrel 1 and the lens barrel 4 can be expanded. Lens barrel 4
Holds the optical system consisting of the lens group 11, holds the operation shaft 2 in a fitted state, fixes the linear guide key 6 by screwing, and fits the fixed lens barrel 1 with the inlay diameter 4D. The linear guide key 6 is fitted in the guide hole 1b of the fixed lens barrel 1 so as to be linearly movable. At the same time, leaf spring 5
Is sandwiched between the lens barrel 4 and the fixed lens barrel 1, and is spring-pressed in a direction in which the distance between the fixed lens barrel 1 and the lens barrel 4 is narrowed, that is, in the direction in which the focal point is moved backward. It is stored. In the lens barrel incorporated in the above state,
As shown in FIG. 1, the space between the fixed lens barrel 1 and the lens barrel 4 is such that the end face 2m of the operation shaft 2 abuts the end face 1m of the fixed lens barrel 1 by pressing the leaf spring 5, and the focus adjustment nut 7 End face 7a of lens barrel 4
It is kept in contact with the inner side wall 8a of the decorative frame 8 integrated with. In this state, when focusing the infinity position of the optical system including the lens group 11, the focus adjustment nut 7 may be rotated.

That is, when the focus adjusting nut 7 is now turned in the direction of loosening the screw, the end face 7a is in contact with the inner wall 8a of the decorative frame 8. Therefore, the screw for pushing the operating shaft 2 backward with the straight guide screw 9 as a guide. Although thrust is generated, since the end surface 2m of the operating shaft 2 is in contact with the fixed lens barrel 1, the lens barrel 4 overcomes the repulsive force of the leaf spring 5 and the distance between the lens barrel 4 and the fixed lens barrel 1 increases, that is, the lens system moves. Move in the direction in which it is manipulated. On the contrary, when the focus adjusting nut 7 is rotated in the screwing direction, the repulsive force of the leaf spring 5 causes the lens barrel 4 and the fixed mirror 4 to rotate in the opposite direction. The distance between the torso 1 moves in the fitted direction. Focusing operation at an infinite position can be performed by utilizing this action.

Next, the focusing operation of the lens barrel according to the change of the photographing distance is performed by the rotation operation of the operation member 3. At the time of focusing work at an infinite position, the operation member 3 is stored at a position that does not participate in the distance regulation between the lens barrel 4 and the fixed lens barrel 1, but if the operation member 3 is rotated here, for example, When the screw is rotated in the loosening direction, the operating member 3 is moved backward (to the right in the drawing) by the screw thrust with the operating shaft 2, and its end face 3u contacts the abutting face 1u of the fixed lens barrel 1. The focus position does not change until it moves in the contact direction and comes into contact, but the end faces 3u and 1u come into contact with each other,
When the rotation operation is further performed, the lens is extended in the direction of increasing the distance between the lens barrel 4 and the fixed lens barrel 1. At this time, the lens barrel 4
Moves overcoming the repulsive force of the leaf spring 5 and rotates the operating member 3 in the opposite direction. Now, if the repulsive force of the leaf spring 5 causes the above-mentioned interval, the operating member 3 moves in the opposite direction. When it moves to the position of infinity, the stop member moves to the operation shaft 2 described above, and the operation member 3 is not involved. As described above, the focusing operation at the photographing distance other than the infinite position can be performed by the rotational movement of the operation member 3.

FIG. 2 is a side sectional view in which the correction frame 10 for visible light is attached to the lens barrel (first shown) of the present invention. Referring to FIG. 2, in the figure, the dimension from the mounting abutment surface 10a of the visible light correction frame 10 to the decoration frame 8 to the abutment end surface 7c of the focus adjustment nut 7 is L, and the decoration of the lens barrel is shown. The dimension from the end surface of the filter mounting screw portion of the frame 8 to the inner wall 8a with which the focus adjustment nut 7 abuts is L1, and the focus adjustment nut 7 visible light correction frame
The dimension from the contact surface with 10 to the contact surface with the inner wall 8a of the decorative frame 8 is l. The amount of deviation between the focusing position in the shooting wavelength range, the focusing position in the visible light range, and the focusing position in the shooting wavelength range, that is, the correction amount Δ
It will be described as x. As described above, FIG. 2 shows the lens barrel having the mechanism and structure described in FIG. 1 with the visible light correction frame 10 attached to the filter mounting screw portion. In this state, a focusing operation at an infinite position is performed by rotating the focus adjusting nut 7. At this time, the relationship between L, L1 and l satisfies the following equation.

l = (L1 + Δx) −L (1) In the formula (1), the focal point fb is shortened, that is, moved in the direction in which the space between the decorative barrel 4 and the fixed lens barrel 1 is narrowed to form the in-focus point. Consider the correction amount as (+), and in the opposite case (-)
I think.

In addition, according to the configuration of the present invention, since the automatic correction mechanism uses the repulsive force of the leaf spring 5, when the focal length fb is corrected from the short direction to the long direction, the L dimension corresponding to the correction frame is corrected. If you increase the amount by Δx, you can correct it automatically by attaching the correction frame to the filter mounting screw. If you correct fb in the shorter direction, you cannot correct it in the shorter direction than initially set. In the case of near-infrared imaging, etc., fb is shortened, and the correction amount Δx is considered to be (−) and the equation (1) is satisfied by considering L as a reference. , L1 and l should be set. Therefore, the first
Focus on the infinity position when shooting in the near infrared region in the state shown in the figure,
During visible light shooting, the focus adjustment nut 7 is adjusted by the correction amount Δx.
If the visible light correction frame 10 set to push the end face of the lens is attached and used as shown in FIG. 2, the end face of the focus adjustment nut is pushed by the correction amount Δx, and the lens barrel 4 corrects the correction amount Δx.
It is moved in the direction that is repeated by the amount and is automatically corrected. As the visible light correction frame, an infrared cut filter or the like may be used as shown in FIG. Further, when the focusing position of the photographing wavelength is corrected by the configuration of the focusing device of the present invention, it can be performed without changing the relationship between the operation member 3 and the fixed lens barrel 1. Correction is possible not only at infinity position but also over the entire shooting distance, and if a distance scale or a mark corresponding to the scale is displayed on the operating member 3, the distance that can be used in common even if the shooting wavelength is different It has the advantage of displaying scales.

〔effect〕

As described above, according to the focusing device of the lens barrel for an optical device according to the present invention, the fixed lens barrel 1 which is a member for mounting the optical device body and the fixed lens barrel are fitted to each other via the linear guide key. In the lens barrel for an optical device including the lens barrel 4 which is an optical system holding member, a leaf spring that is sandwiched between the fixed lens barrel 1 and the lens barrel 4 and constantly urges the two in a direction in which they approach each other. 5, an operation shaft 2 fitted to the lens barrel 4 so as to be movable only in the optical axis direction is provided, and the operation shaft 2 is an operation member of which a part is projected to the outside on the fixed lens barrel 1 side. 3 and the focus adjusting nut 7 is screwed to the lens barrel 4 side, and one end face in the axial direction is fixed to the fixed lens barrel 1.
And the end face of the focus adjusting nut 7 is brought into contact with the inner side wall 8a of the decorative frame 8 fixed to the lens barrel 4, so that it is sandwiched between the fixed lens barrel 1 and the lens barrel 4, and By rotating the focus adjustment nut 7, the lens barrel 4 is moved in the optical axis direction to perform an in-focus operation at an infinite position of the optical system, and by rotating the operation member 3, the operation member 3 is rotated.
The lens barrel 4 is moved in the optical axis direction against the repulsive force of the plate spring 5 by the thrust force generated by pressing the fixed lens barrel 1 against the fixed lens barrel 1, and a change occurs in the shooting distance other than the infinity position. By having the structure of the focusing device for the lens barrel for optical equipment, which is characterized by performing the focusing operation, the lens barrel 4 is fixed to the fixed lens barrel 1 by the leaf spring 5 without using a conventional helicoid screw. The operation shaft 2 in which the decorative frame 8 fixed to the main body is always urged in a direction to be closely approached, is fitted into the lens barrel 4 so as to be movable only in the optical axis direction, and the operation member 3 is screwed to the fixed lens barrel 1 side. Then, by rotating the focus adjusting nut 7 with the focus adjusting nut 7 abutting against the inner wall 8a of the decorative frame 8 screwed and one end surface of the operating shaft 2 abutting against the fixed lens barrel 1. , The lens barrel 4
Can be moved in the optical axis direction to perform the focusing operation at the infinite position of the optical system, and the operation member 3 screwed to the fixed lens barrel 1 side can be rotated to move the operation member 3 The lens barrel 4 is moved in the optical axis direction against the repulsive force of the leaf spring 5 by the thrust generated on the operation shaft 2 by pressing it against the fixed lens barrel 1 to change the photographing distance other than the infinity position. There is an effect that the accompanying focusing operation can be performed, and at that time, the end faces of the focus adjusting nut 7 and the operating member 3 are constantly pressed against the abutting surface of the decorative frame 8 or the fixed lens barrel 1 by the pressing force of the leaf spring 5. Since the rotation of the focus adjusting nut 7 and the operation member 3 is blocked, the focusing position does not shift even under adverse conditions such as vibration and shock, and the helicoid focusing device is provided. It is possible to eliminate the need for a locking mechanism for the operating member as in the case of By simplifying the component structure, making it possible to make small component parts, and removing the helicoid screw, the shape of the molded part becomes a simple shape when promoting resinification of the part, and in terms of accuracy and cost Also improved. There is an effect to provide a focusing device having high productivity, particularly a device suitable as a focusing device for a lens barrel for an optical device such as a lens barrel for a CCTV camera having a small extension amount.

Further, according to the present invention, in the above-described focusing device, a visible light correction frame 10 detachably attached to the lens barrel is provided, and the focus adjustment nut is attached by attaching the visible light correction frame 10. 7 is pressed and moved toward the fixed lens barrel 1 side, and the lens barrel 4 is moved in the optical axis direction to be adjusted to the in-focus position corresponding to the wavelength range of visible light photography, and the visible light correction frame 10 is adjusted. By removing the focus adjustment nut 7, the focus adjustment nut 7 is released and automatically corrected to a focusing position different from the visible light wavelength range, so that the visible light correction frame 10 moves in the optical axis direction. A focusing device for a lens barrel for an optical instrument, characterized in that a dimension 1 in the optical axis direction of the focus adjusting nut 7 is set based on the width dimension L and a correction amount Δx related to the focusing position in the photographing wavelength range. By having the configuration, the user can add one lens barrel There is an effect that it is possible to provide a function capable of easily switching the in-focus position of photographing with a simple configuration by simply attaching and detaching the visible light correction frame 10 according to the wavelength used by the user.

[Brief description of drawings]

FIG. 1 is a side sectional view of an essential part of an embodiment of a lens barrel for a CCTV camera to which the present invention is applied, and FIG. 2 is a side sectional view showing another embodiment to which the present invention is applied. FIG. 3 is a side sectional view of a main part in which an infrared cut filter is incorporated in a visible light correction frame. 1 …… Fixed lens barrel 1a …… Mounting screw 1b …… Guide hole 1D …… Inlay diameter 1m …… Abutting surface 1u …… Abutting surface 2 …… Operating shaft 3 …… Operating member 3u …… End surface 4 …… Lens barrel 4D …… Inlay diameter 4a …… Guide groove 5 …… Leaf spring 6 …… Straight guide key 7 …… Focus adjusting nut 8 …… Decorative frame 8a …… Inner wall 9 …… Straight eye screw 10 …… For visible light Correction frame

Claims (2)

[Scope of utility model registration request] 1. An optical device comprising a fixed lens barrel 1 which is a mounting member for an optical device main body, and a lens barrel 4 which is an optical system holding member fitted to the fixed lens barrel through a linear guide key. In the lens barrel for use, a leaf spring 5 is provided which is sandwiched between the fixed barrel 1 and the lens barrel 4 and which always urges the fixed lens barrel 1 and the lens barrel 4 toward each other so that the lens barrel 4 can move only in the optical axis direction. A fitted operating shaft 2 is provided. The operating shaft 2 is screwed with an operating member 3 of which a part is projected to the outside on the fixed lens barrel 1 side, and a focus adjusting nut 7 is attached on the lens barrel 4 side. Together with screwing,
The one end face in the axial direction is brought into contact with the fixed lens barrel 1, and the end face of the focus adjustment nut 7 is brought into contact with the inner side wall 8a of the decorative frame 8 fixed to the lens barrel 4, whereby the fixed lens barrel 1 is attached. And the lens barrel 4, and by rotating the focus adjustment nut 7, the lens barrel 4
Is moved in the optical axis direction to perform the focusing operation at the infinite position of the optical system, and the operation member 3 is rotated to push the operation member 3 against the fixed lens barrel 1 with the thrust force. A lens barrel for optical equipment, characterized in that the lens barrel 4 is moved in the optical axis direction against the repulsive force of the leaf spring 5 to perform a focusing operation in accordance with a change in the shooting distance other than the infinity position. Focusing device. 2. The focusing device according to claim 1, wherein the correction frame for visible light is removably attached to the lens barrel.
By attaching the visible light correction frame 10, the focus adjustment nut 7 is pressed and moved toward the fixed lens barrel 1 side, and the lens barrel 4 moves in the optical axis direction, so that the wavelength of visible light imaging is increased. Is adjusted to a focusing position corresponding to the range, and by removing the visible light correction frame 10, the pressure on the focus adjustment nut 7 is released, and the focusing position is automatically set to a different focusing position from the visible light wavelength range. To be corrected,
The dimension 1 of the focus adjustment nut 7 in the optical axis direction is set based on the width dimension L of the visible light correction frame 10 in the optical axis direction and the correction amount Δx related to the focusing position in the photographing wavelength range. Focusing device for lens barrel for optical equipment.