JPH0258010A - Video camera - Google Patents

Abstract

PURPOSE:To constitute a video camera at a low cost, in light weight and in miniaturization and to obtain perfect dust-proof construction by executing variable magnification through the use of a first mobile mechanism and performing focusing by means of a second mobile mechanism. CONSTITUTION:The mobile mechanisms are assembled in a camera main body 1 on which a receiving seat 9 is loaded by a bis beforehand in the way that a lens barrel 2 with a group of intermediate lenses L2, the protective frames 7 and 8 of a group of image-forming lenses L3 as well as a crank lever 10 are inserted and fixed in the camera main body 1, on which a screw seat 12 is loaded by a bis afterward. Then, a supporting seat 15 is loaded on the outer wall of the lens barrel 2 and the crank lever 10 is supported not to be tilted. Thus resistance against turning is reduced, and the constitution at a low cost, in reduced weight and in miniaturization can be realized.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a video camera, and particularly to a video camera suitably used for surveillance.

[Prior art] Surveillance video cameras are most often installed in a fixed position and used to take pictures of people, objects, etc. that come to a certain place. It was assumed that this was due to lens replacement. However, recently there has been an increasing demand for surveillance video cameras with a zoom mechanism. In order to meet this demand, a surveillance video camera consists of a focusing objective lens group that can be moved in the optical axis direction by a helicoid screw, and a front lens group and a rear lens group that can be moved in the optical axis direction by cam tubes. A conventionally known zoom mechanism using a variable power lens can be easily adopted.

FIG. 4 is a sectional view of a zoom lens structure showing an example of a conventionally known zoom mechanism.
The focusing objective lens groups Vl and V2 move in the optical axis direction by rotating the cam cylinder C in the optical axis direction with the zoom operation handle H, and the cam grooves CI and C provided in the cam cylinder C are
2 and straight inner grooves bl and b parallel to the optical axis provided in the fixed barrel B.
2 are a front lens group and a rear lens group for variable magnification, which move in the optical axis direction, and M1 and M1 are a fixed front lens group and a rear lens group, respectively.

It requires machining precision, the lens barrel becomes thick and long, and even though the linear guide grooves bl and b2 of the fixed barrel B can be covered as shown, the zoom operation handle H can be moved. It is difficult to completely cover the necessary circumferential groove of the fixed body B, even if it is covered with a well-known elastic cover such as rubber, and therefore there is a problem that complete dustproofing cannot be achieved. be. Therefore, adopting such a zoom mechanism would significantly increase the cost and weight of surveillance video cameras, making them larger, and making them more likely to be damaged by dust during long-term use. Become. In addition, when the most frequently used camera is fixed and there is no need to change the angle of view or shooting distance,
Another problem is that the angle of view and shooting distance cannot be locked.

The present invention can change the angle of view and lock the angle of view and shooting distance with a relatively simple mechanism, and can be configured to be relatively inexpensive, lightweight, and compact, and can easily achieve complete dustproofing. The purpose of the present invention is to provide a video camera suitable for monitoring that can perform the following tasks.

[Means to solve the problem]

The present invention provides an optical system consisting of at least three lens groups, a solid-state image sensor that converts light incident on the optical system into an electrical signal, and a movement that changes the relative position of the lens group of the optical system and the solid-state I-most image element. In a video camera having a mechanism,
The moving mechanism includes a first moving mechanism that moves one of the lens groups of the optical system, and a second moving mechanism that moves another lens group or the solid-state image sensor, and the first moving mechanism The present invention is a video camera characterized in that magnification is changed and focusing is performed by a second moving mechanism, and this configuration makes it possible to achieve the above object.

[Function] That is, in the video camera of the present invention, magnification is changed by moving one of the lens groups of the optical system in the optical axis direction, and the other lens group or the optical axis of the solid-state image pickup device is moved. Since focusing is performed by moving in the direction, conventional magnification is changed by moving the two front and rear lens groups for variable power in the optical axis direction, and focusing is performed by moving the focusing objective lens group in the optical axis direction. Compared to the case where a zoom mechanism is adopted, the structure is simpler because there are fewer elements that move in the optical axis direction, and it is also easier to move the variable power lens group, focusing lens group, or solid-state image sensor in the optical axis direction. Without using a cam cylinder that requires precision and has a complicated structure, it is possible to easily create a structure such as a crank mechanism, for example, without requiring high processing precision, and sealing the part where the drive operation part penetrates the camera body. It is easy to use, completely dustproof, and has a mechanism that can be easily locked.
It can be configured to be relatively inexpensive, lightweight, and small.

〔Example〕

The present invention will be explained below using illustrated examples.

FIG. 1 is an external perspective view showing an example of the video camera of the present invention;
FIG. 2 is a schematic sectional view showing the optical system, and FIG. 3 is a partially enlarged view showing the movement mechanism of the intermediate lens group and the imaging lens group.

1 to 3, 1 is a camera body, 2 is a fixed lens barrel that is integrally assembled with the camera body 1 by means not shown, 1 is an objective lens group, L2 is an intermediate lens group, L3 is an imaging lens group, E is a solid-state image sensor, and J
is a connection terminal attached to the rear end wall of the camera body 1.

The objective lens group L1 is directly fitted into the lens barrel 2,
It is fixed to the lens barrel 2 by a tightening screw ring 3. The solid-state image sensor E has a holding frame 4 as shown in the figure.
Alternatively, like the objective lens group L1, it is fixed to the lens barrel 2 by a tightening ring 5. The intermediate lens group L2 and the imaging lens group L3 have their holding frames 7 and 8 slidably fitted to the inner diameter of the lens barrel 2, respectively, and are operated by a moving mechanism whose details are shown in FIG. It is movable in the axial direction.

The moving mechanism shown in FIG. 3 moves the lens barrel 2 into the intermediate lens group L2 within the camera body l to which the retainer seat 9 has been attached using screws.
The crank lever 10 is also inserted and fixed together with the holding frames 7 and 8 of the imaging lens group L3 as shown in the figure, and then the drive shaft 11 is inserted so that the rectangular bar 11a at the tip thereof is attached to the crank lever 10. Insert it into the square hole 10a of the
After that, attach the screw seat 12 to the camera body 1 with a screw, screw the lock knob 13 onto the screw seat 12, and attach the operation knob 14 for moving the lens group to the tip of the drive shaft 11.
It is assembled by attaching with screws. A support seat 15 is attached to the outer wall of the lens barrel 2, which supports the crank lever 10 so that it does not tilt, thereby reducing resistance to rotation.

The intermediate lens group L2 and the imaging lens group L3 are moved in the optical axis direction by the moving mechanism shown in FIG. With no pressure applied, press operation knob 1.
4 to the right or left, the crank lever 10 rotates to the right or left via the drive shaft 11.
The crank pin 10b installed in the lens barrel 2 passes through the guide groove 2a provided in the lens barrel 2 and engages with the circumferential groove 7a or 8a provided in the holding frame of the intermediate lens group L2 or the imaging lens group L3. It is done by being present. As a result, by moving the intermediate lens group L2 and the imaging lens group 3 in the optical axis direction, it is possible to change the magnification ratio, that is, the angle of view and the focusing distance. Then, by screwing in the locking knob 13, its tip and holder squeeze the flange portion 11b of the drive shaft 11 with the seat 9, and by preventing the drive shaft 11 from rotating, the angle of view and the shooting distance for focusing can be adjusted. Can be locked. Note that the locking knob 13 is screwed in and the drive shaft 11 is
There is a risk that the drive shaft 11 will rotate when pushing the flange portion 11b of If the knob 13 can be moved only in the axial direction of the drive shaft 11 by means such as a lever or a spring, the drive shaft 11 will not rotate when locked.

The present invention is not limited to the example shown in FIG. 2 in which the intermediate lens group and the imaging lens group are movable and the fixed objective lens group is directly fixed to the lens barrel. The lens group or solid body may be configured so that the image element can be moved in the optical axis direction. Also, the movement mechanism for the lens group, etc. is not limited to a crank mechanism, and one lens is 4 cm or more.
(also).

〔Effect of the invention〕

In the video camera of the present invention, one of the lens groups of the optical system is movable in the optical axis direction, and the other lens group or the solid-state image sensor is movable in the optical axis direction, so that the angle of view can be changed. By making this possible, the structure can be made cheaper, lighter, and smaller than when using a conventionally known zoom mechanism, and it also requires a crank mechanism to move the lens group and solid-state image sensor. If you use
Another effect is that the part where the operating section of the moving mechanism passes through the camera body can be easily sealed, resulting in a completely dust-proof structure.

[Brief explanation of the drawing]

FIG. 1 is an external perspective view showing an example of the video camera of the present invention;
Fig. 2 is a schematic cross-sectional view showing the optical system, Fig. 3 is a partially enlarged view showing the movement mechanism of the intermediate lens group and the imaging lens group, and Fig. 4 is a longitudinal cross-section of a zoom lens structure showing an example of a conventional zoom mechanism. It is a surface. 1... Camera body, 2... Lens barrel, 2
a...Guide groove, Ll...Objective lens group,
L2... Intermediate lens group, L3... Imaging lens group, E... Solid-state image sensor, J... Connection terminal, 4.
7.8... Holding frame, 7a, 8a... Circumferential groove, 3.5... Tightening screw ring, 9... Receiving seat, 10
...Crank lever 10a...Square hole part, 11.
...Drive shaft, lla square rod part, 11b...flange part, 12...screw seat, 13...lock knob, 14...operation knob, 15...support seat. Figure 3

Claims (2)

[Claims] (1) An optical system consisting of at least three lens groups, a solid-state image sensor that converts light incident on the optical system into an electrical signal, and a movement mechanism that changes the relative position of the lens groups of the optical system and the solid-state image sensor. In the video camera, the moving mechanism includes a first moving mechanism that moves one of the lens groups of the optical system, and a second moving mechanism that moves another lens group or a solid-state image sensor, A video camera characterized in that a first movement mechanism performs magnification change and a second movement mechanism performs focusing. (2) The video camera according to claim 1, wherein a lock operation member is provided outside the camera body together with the movement operation members of the first and second moving mechanisms.