JPS5967504A - Interlocking mechanism of auxiliary lens system for variable focus camera - Google Patents

Abstract

PURPOSE:To simplify the mechanism of a camera by turning an auxiliary lens system onto the photographing optical axis around a bar as a turning center in the stage of focusing. CONSTITUTION:An extender 5 which holds an auxiliary lens system 6 is fitted and supported turnably to a bar 3 fixed to a supporting cylinder 1 which holds a main lens system 2. Said extender is pressed to the rear end face side of a lens barrel 10 and is so energized as to turn to the photographing optical axis side. The bar 3 which guides rectilinearly the main lens system 2 in the stage of focusing is used as the turning center for the auxiliary lens system 6 in the above-mentioned way. The system 6 moves in and out on the photographic optical axis to operate from a standard photographing state to a telephoto photographing state or conversely cooperatively with the forward and backward movement of the lens barrel 10 together with the system 2 in the stage of changing over the focal length.

Description

Detailed Description of the Invention The present invention has a main lens system and a sub-lens system, and the sub-lens system moves in and out of the photographing source axis in conjunction with the movement of the main lens system, thereby changing the focal length of the photographing optical system. The present invention relates to a sub-lens system interlocking mechanism for a variable-focus camera that can switch between.

Conventionally, in addition to the main lens system, a sub-lens system is provided inside the camera, and as the main lens moves, the sub-lens system moves in and out of the photographing optical axis as necessary (/C). A camera capable of shooting at different focal lengths was disclosed in Japanese Patent Laid-Open No. 52-76919, Japanese Patent Publication No. 54-33027
It is known by the number etc.

For example, FIG. 1 shows an example of a conventional optical system capable of standard photography and telephoto photography. In the figure, L1 is the main lens system with lens shutter S, L2 is the sub-lens system, and F is the film. In the shooting state, only the main lens system L1 is used, but in the telephoto shooting state, the main lens system L1
As the lens shutter S moves forward, the sub lens system L2 is positioned on the optical axis at the rear of the lens shack S.

FIG. 2 is a schematic cross-sectional view of a conventional example of a variable focus camera configured using the optical system shown in FIG. 1. First, the configuration will be explained.

The support tube 1 holds the main lens system 2, and is fitted and supported by the constituent members of the lens barrel section 10 at two positions. The lens barrel section 10 is provided with a shutter device 4 on the rear side of the support tube 1, and further on the rear side, an extender 5 holding a sub-lens system 6 is fitted into the constituent members of the lens barrel section 10. The extender shaft 7 is mounted so as to be rotatable about the entire center of the extender shaft 7, and a lever spring 8 is biased so as to press against the rear end surface of the lens barrel portion 10 and rotate toward the photographing optical axis side.

Further, a support bar 9 is fixed to the lens barrel section 10 in parallel to the photographing optical axis, and the support bar 9 is slidably fitted and supported directly in a holding frame section 1102 fixed to the front surface of the camera body 20. At the same time, the lens barrel part 10 also fits into a guide bar 12 whose both ends are fixed to the holding frame part 11, and with the guide bar 12 as a guide, it moves together with the support bar 9 in the front-rear direction of the camera, that is, the photographing optical axis. It is possible to slide in the direction. A part of the dark box section in which a bellows 14 whose end surfaces are respectively fixed to the rear end of the lens barrel section 10 and the light shielding frame plate 13 on the side of the camera body 20 is arranged to block light from the surroundings. Fully formed. Note that 15 is a sprocket, and 21 is a camera exterior case.

In the standard photographing state shown in FIG. 2(a), the sub lens system 6 is retracted from the photographing optical path, but when the lens barrel section 10 is moved to the front side of the camera, the extender 5
rotates, the sub lens system 6 is positioned on the photographing optical axis, and the second
The camera switches to the telephoto shooting state shown in Figure (b).

However, in this configuration, the bar 3 that guides the main lens system 2, which is linearly extended during focusing, and the shaft 7 that holds the sub-lens thread 6 are separate bodies, so the number of parts is large (
In addition, when the main lens system and the sub lens system are combined on the photographing optical axis, optical parallel eccentricity or inclination occurs, which requires time and effort to adjust, and optical acuity cannot be satisfied. there were.

The present invention eliminates the drawbacks of the conventional example described above, simplifies the structure, and facilitates adjustment (and improves the optical performance of the photographic optical system in which the main lens system and the sub lens system are combined). It is our aim to provide a sub-lens system interlocking mechanism for a variable focus camera that can also satisfy the focal length.

Embodiments of the present invention will be described below based on the drawings.

FIG. 3 is a schematic cross-sectional view of the main part of one embodiment of the present invention,
) is the standard shooting condition, (b) is the telephoto shooting condition, respectively.
It shows.

In the figure, the structure is particularly different from the conventional example shown in FIG. 2 above. It is rotatably supported on a pedestal, pressed against the rear end surface of the lens barrel section 10 by a cover spring 8, and urged to rotate toward the shooting source axis.

In this way (1), the bar 3 that linearly guides the main lens system 2 during focusing is used as the center of rotation of the sub lens system 6, and when changing the focal length, the lens barrel section 1 together with the main lens system 2
0 moves back and forth, the camera moves from the standard shooting state shown in FIG. 3(a) to the telephoto shooting state shown in FIG. 3(b) 1, or vice versa.5 f%li The lens system 6 moves in and out on the photographing optical axis.

As explained above, the present invention has a configuration in which the lens system rotates toward the shooting source axis around a bar that moves linearly and serves as a guide for the main lens system when focusing the photographic optical system. This not only simplifies the mechanism of the camera, but also facilitates its adjustment, making it easier to satisfy optical performance requirements when combining the main lens system and the sub lens system. It is effective.

[Brief explanation of drawings]

Figure 1 is an explanation of an example of an optical system used in a variable focus camera, and Figure 21 is a schematic cross-sectional view showing the configuration of a conventional variable focus camera, where (a) is a standard shooting state and (b) is a telephoto camera. FIG. 3 is a schematic sectional view showing an embodiment of the present invention, in which (a) is a standard photographing state and (b) is a telephoto photographing state. 1...Support tube, 2...Main lens system, 3・Bar, 4
... Nyanota device, 5... Extender, 6... Sub-lens system, 8... Spring, 10... Lens barrel section, 20...
・Camera body. Figure 2 (a) Figure 3 (0) Figure 3 - (b)

Claims (1)

[Claims] What is the main lens system and the sub lens system? The focal length of the photographing optical system can be changed by moving the main lens system in conjunction with the movement of the main lens system and moving in and out of the photographing source axis, and A variable-focus camera in which only the main lens system is guided by a bar that moves in a straight line, and the focusing of the photographing optical system is performed by controlling the movement of the bar. A sub-lens system interlocking mechanism for a variable-focus camera, characterized by a rotatable structure.