JPH0520043U - Lens movement mechanism - Google Patents

Abstract

(57) [Abstract] [Purpose] It is an object of the present invention to provide a lens moving mechanism capable of easily performing zoom adjustment and focus adjustment of a zoom lens mounted on a surveillance video camera. [Structure] Zoom lens zoom adjustment axis 25 and focus adjustment axis 30
Position so as to be embedded in the outer surface of the camera, and the presser plate 300 and the spring plate 400 are built into the camera body. It is characterized in that a proper friction is applied to the shafts, and after the adjustment, the holding plate 300 is brought into a pressure contact state to clamp and fix the respective adjustment shafts.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 The present invention relates to a lens moving mechanism of a zoom lens barrel, and more particularly to a lens moving mechanism of a zoom lens barrel mounted on a surveillance video camera.

[0002]

[Prior Art]

 Since surveillance video cameras are most commonly used to shoot people or things that have come to a certain place in a fixed manner, keep the angle of view constant and change the angle of view by changing the lens. It was due to. However, recently there has been an increasing demand for surveillance video cameras with a zoom mechanism. To meet this demand, a surveillance video camera can be moved in the optical axis direction by a helicoid screw. It consists of a focusing objective lens group and a front lens group and a rear lens group that can be moved in the optical axis direction by a cam barrel. It is easy to adopt a conventionally known zoom mechanism using a variable power lens.

However, according to the conventional zoom mechanism, the structure becomes complicated and high processing accuracy is required. Further, the lens barrel becomes thick and long, and the groove for zooming operation is long. There was a problem that it was not possible to achieve complete dust protection. Therefore, if such a zoom mechanism is adopted, the cost and weight of the surveillance video camera will greatly increase, and the surveillance video camera will become large in size, and dust will cause an obstacle during long-term use. . Another problem is that if the most frequently used camera is fixed and the angle of view and shooting distance do not need to be changed, the angle of view and shooting distance cannot be locked.

In order to solve these problems, the present applicant has previously proposed a lens moving mechanism for a zoom lens barrel as shown in FIG.

Reference numerals L1, L2, and L3 are an objective lens group, a variable power lens group, and an imaging lens group, respectively, which constitute an optical system of a zoom lens, and the variable power lens group L2 and the imaging lens group L3 are respectively optical axes. The zoom magnification and the focus position are set by adjusting the direction.

When the variable power lens unit L2 is moved, the crank pin 2 attached to the tip of the crank lever 1A at the lower end of the rotary shaft 1 that engages with the circumferential groove 3 of the lens frame operates in an arc shape in the optical axis direction. Done by.

The operation of the crank pin 2 is performed by rotating an adjusting knob 6 fixed to an adjusting shaft 4 which can be coaxially and integrally connected to the rotating shaft 1.

After adjusting the zoom magnification, when the locking knob 8 screwed into the mounting seat 7 of the lens barrel is screwed in, the flange 5 of the rotating shaft 1 is sandwiched between the lower end surface of the locking knob 8 and the base plate 9 The position of the lens unit L2 in the optical axis direction is fixed.

On the other hand, with respect to the image forming lens group L3, the only difference is that the eccentric pin 2A of the adjusting shaft 4A is directly engaged with the circumferential groove 3A of the lens frame. It is adjusted by the adjusting knob 6A similar to the case, and is fixed by the locking knob 8A.

By adopting such a lens moving mechanism, the lens barrel can be made smaller and lighter, and the zooming and focusing can be adjusted extremely easily and reliably.

[0011]

[Problems to be solved by the device]

 However, the above adjustment knobs are installed on the outer surface of the camera body, and there is no friction in the unlocked state, so carelessly touching them when adjusting or operating the locking knobs. Adjustment position may be misaligned. In addition, some lens systems require the focus position to be corrected each time the magnification is changed, so such a method of separately locking the zoom lens group and the imaging lens group is suitable for such a zoom lens barrel. There is still a problem to say.

[0012] As another usage, even if the lock screw is not locked, it is always tightened at an appropriate position so that friction is always applied, adjustment is performed in that state, and it is left as it is after adjustment. However, in this case, there are many problems such as torque fluctuation due to how long the tightening is done to keep the rotation torque constant and changes over time, so it cannot be said to be very suitable.

The present invention can change the angle of view and lock the angle of view and the shooting distance with a relatively simple mechanism, and can be constructed relatively inexpensively, lightly, and compactly, and is completely dustproof. It is an object of the present invention to provide a lens moving mechanism suitable for a surveillance video camera that can easily achieve the above-mentioned problems and can solve the above problems.

[0014]

[Means for Solving the Problems]

 The above object is to provide an optical system including at least three lens groups, a solid-state image sensor that converts light incident on the optical system into an electrical signal, and a moving mechanism that changes the relative position of the lens group and the solid-state image sensor of the optical system. And a second moving mechanism for moving one of the other lens group or the solid-state image pickup device, the moving mechanism moving one lens group of the lens groups of the optical system. Then, the moving operation of the first and second moving mechanisms of the video camera in which the first moving mechanism performs zooming and the second moving mechanism performs focusing is performed by rotating shafts, and each rotating shaft adjusts its position. At times, friction is applied by a common elastic member, and after position adjustment, it is simultaneously fixed by a common fixing member. It is achieved.

[0015]

【Example】

 Hereinafter, the present invention will be described with reference to illustrated examples.

FIG. 1 shows an example of a zoom lens barrel for a video camera equipped with a lens moving mechanism of the present invention, wherein L1, L2 and L3 are an objective lens group, a variable magnification lens group and an imaging lens, respectively. Each optical system of the group.

The lens group L1 is fitted into the end portion of the lens barrel 10 and is fixed by a tightening screw 11 and the lenses L2 and L3 are held by respective lens frames 12 and 13, and the lens barrel is It is built into the inner circumference of 10 so that it can move in the optical axis direction.

Reference numeral 20 denotes a rotation shaft rotatably supported between a pair of support plates 24 provided on the outer peripheral portion of the lens barrel 10, the upper end of which is a prism 21 and the lower end of which is a crankpin 23. The crank lever 22 provided is integrated.

The rotation shaft 20 is located on a cross section including the optical axis of the optical system, and the crank pin 23 has an arc shape provided on the lens barrel 10 as shown in FIG. It is fitted in a circumferential groove 12A formed on the outer periphery of the lens frame 12 through the elongated hole 10A.

Further, reference numeral 25 is a variable power adjusting shaft which is an adjusting member connected to the upper part of the rotating shaft 20, and the square hole portion 26 at the lower end thereof engages with the prism portion 21 to integrally rotate the rotating shaft 20. There is.

On the other hand, reference numeral 30 denotes a focus adjusting shaft which is an adjusting member rotatably supported by a supporting portion 10B formed by the lens barrel 10, and is provided at the lower end as shown in FIG. 2 (b) showing its plan view. An eccentric cam 31 is fitted in a circumferential groove 13A formed on the outer circumference of the lens frame 13.

The focus adjusting shaft 30 is located on a cross section including the optical axis of the same optical system as the rotating shaft 20.

Both the variable power adjustment shaft 25 and the focus adjustment shaft 30 are provided with flanges 27 and 32, and are supported by the base plate 100 of the video camera main body, and the slits at the upper ends of the two are attached to the outer surface of the mounting seat 200 on the outer wall of the camera body. I am looking into.

Reference numeral 300 denotes a holding plate which is interposed between the base plate 100 and the mounting seat 200, and which is a fixing member that presses the respective flanges by inserting the variable power adjusting shaft 25 and the focus adjusting shaft 30 respectively. Further, 400 is a spring plate which is an elastic member for pressing the pressing plate 300 downward.

The holding plate 300 has a fixing screw 40 having a flange 41 screwed to the center thereof, and a slit portion at the upper end thereof is attached to the outer surface of the mounting seat 200 in the same manner as the magnification adjusting shaft 25 and the focus adjusting shaft 30. I'm looking through.

The zoom adjustment and focus adjustment of the zoom lens in the lens moving mechanism of the present invention are performed as follows.

When the fixing screw 40 is appropriately tightened for adjustment, the pressing plate 300 is urged downward by the elastic force of the spring plate 400, and the flanges 27 and 32 are sandwiched between the pressing plate 300 and the main plate 100. Then, a proper amount of friction is applied to the variable power adjustment shaft 25 and the focus adjustment shaft 30.

Therefore, when the variable power adjusting shaft 25 is rotated against the friction with a driver or the like, the rotating shaft 20 is rotated, and the crank pin 23 of the crank lever 22 is rotated as shown in FIG. 2A. The lens frame 12 is moved via the directional groove 12A from the position indicated by the broken line to the position indicated by the alternate long and short dash line, and the variable power adjustment of the variable power lens unit L2 is performed.

On the other hand, when the focus adjusting shaft 30 is rotated against the friction in the same manner, the eccentric cam 31 is rotated, and the lens frame is inserted through the circumferential groove 13A as shown in FIG. 2B. 13 is moved from the position indicated by the solid line to the position indicated by the alternate long and short dash line to adjust the focus of the imaging lens group L3.

In the above-described variable power adjustment and focus adjustment, since the variable power adjustment shaft 25 and the focus adjustment shaft 30 are both held by an appropriate friction, fine adjustment is possible, and the hand is slightly touched. The adjustment position does not easily change due to some external force or posture difference. Furthermore, since they are embedded in the outer surface of the camera body, you can not touch them with your hands or tools carelessly. In extreme terms, general use is sufficient without adding any lock.

After the adjustment, the fixing screw 40 is loosened strongly and rotated in the direction of the hand, and the holding plate 300 is pressed downward by the reaction force of the screw, and the flanges 27 and 32 are strongly pressure-bonded to the main plate 100. Magnification adjustment axis 25 and focus adjustment axis 30 are fixed, which makes the lock stronger.

FIG. 3 shows an example in which the zoom lens barrel having the lens moving mechanism of the present invention is attached to a surveillance video camera, and the zooming adjustment axis 25 and the focus adjustment axis 30 are the video camera body. Since it is exposed on the side of the car, its adjustment is always possible and the work is easy.

Further, FIG. 4 shows that the magnification adjusting shaft 25A, the focus adjusting shaft 30A, and the fixing screw 40A are both directly provided on the lens barrel 10C for accommodating the zoom lens, and the zooming and focusing are adjusted in the lens barrel 10C alone. This is an example of a configuration that can be performed.

In this case, the base plate 100A and the mounting seat 200A with the holding plate 300A and the screw plate 400A interposed therebetween are naturally directly attached and fixed to the lens barrel 10C.

[0035]

[Effect of the device]

 The present invention makes it possible to easily and reliably perform zooming and focus position adjustment in a zoom lens barrel with an extremely simple structure. As a result, it is possible to reduce the size and weight of surveillance video cameras. A lens moving mechanism suitable for adjusting the zoom lens barrel has been provided.

[Brief description of drawings]

FIG. 1 is a sectional view of a zoom lens barrel having a lens moving mechanism according to the present invention.

FIG. 2 is a plan view of a main part of the zoom lens barrel.

FIG. 3 is a perspective view of a video camera equipped with the zoom lens barrel.

FIG. 4 is a perspective view showing another embodiment of the present invention.

FIG. 5 is a sectional configuration diagram of a zoom lens barrel previously proposed by the applicant.

[Explanation of symbols]

 10, 10C Lens barrel 10A Slotted hole 10B Supports 12, 13 Lens frame 12A, 13A Circumferential groove 20 Rotating shaft 21 Square column 22 Crank lever 23 Crank pin 25, 25A Magnification adjusting shaft 26 Square hole 27, 32, 41 Flange 30, 30A Focus adjustment shaft 31 Eccentric cam 40, 40A Fixing screw 100, 100A Base plate 200, 200A Mounting seat 300, 300A Holding plate 400, 400A Screw plate (spring plate) L1 Objective lens group L2 Variable magnification lens group L3 Connection Image lens group

Claims (1)

[Scope of utility model registration request] 1. An optical system including at least three lens groups, a solid-state image sensor for converting light incident on the optical system into an electric signal, and a moving mechanism for changing a relative position between the lens group and the solid-state image sensor of the optical system. And a second moving mechanism that moves one lens group of the optical system lens groups and another one lens group or a solid-state imaging device. The first and second video cameras perform zooming by the first moving mechanism and focus by the second moving mechanism.
The moving operation of the moving mechanism is performed by each rotating shaft,
A lens moving mechanism characterized in that friction is applied to each of the rotary shafts by a common elastic member when the position is adjusted, and they are simultaneously fixed by a common fixing member after the position is adjusted.