Television – Camera – system and detail – Optics
Reexamination Certificate
1997-09-22
2001-04-17
Ho, Tuan (Department: 2612)
Television
Camera, system and detail
Optics
C348S352000
Reexamination Certificate
active
06219098
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to a TV camera lens, and more particularly to a drive controlling technique of a TV camera lens, in which a master lens group moves forward and backward along the optical axis to adjust the flange back length and set the optical system for the macro-shooting.
2. Description of Related Art
In a zoom lens applied in a broadcast TV camera, a master lens group of a taking lens system is moved forward and backward along the optical axis to adjust the flange back length, thereby forming a sharp image of an object on a picture screen. Japanese Patent Publication Nos. 58-1401 and 60-46405 disclose TV camera lenses in which the master lens group is moved forward and backward along the optical axis to set the optical system for the macro-shooting.
That is, a rotary adjustment knob is usually provided at one side of the mount frame (the right side viewed from the front, i.e. the left side of a user) so that rotational force of the adjustment knob can be transmitted to a master lens driving mechanism in a lens mount via a power transmission mechanism such as an assembly of gears. If the user turns the adjustment knob by hand, an image formation position of the TV camera lens can be fine adjusted and the macro-shooting can be performed.
In the TV camera lens in which the master lens group is moved to perform both the flange back length adjustment and the macro-shooting, however, since the normal shooting is usually performed after the flange back length adjustment is completed, and the macro-shooting is performed as the need arises during the normal shooting, it is difficult to correctly return the master lens group to the initially-adjusted position of the proper flange back length when the shooting is switched from the macro-shooting to the normal shooting.
In a well-established technique, the master lens group is moved for the purpose of achieving special effects such as obscuring a shot image. In the conventional TV camera lens, however, since the master lens group is moved with the rotation of the adjustment knob provided at the side of the casing and the rotational force is mechanically transmitted via the assembly of gears or the like, it is difficult to smoothly move the master lens group and naturally obscure the shot image.
SUMMARY OF THE INVENTION
The present invention has been developed in view of the above-described circumstances, and has as its object the provision of a TV camera lens which is able to correctly and repeatedly return a master lens group to a position of a proper flange back length after the macro-shooting and smoothly move the master lens group to naturally obscure the shot image.
To achieve the above-stated object, a TV camera lens according to the present invention which moves a master lens group, arranged in a lens mount of a lens body, forward and backward along the optical axis in accordance with operation of either one of the first and second external operating members, so as to adjust the flange back length and set the optical system for the macro-shooting, comprises: a flange back length controller for outputting the first electric signal instructing the master lens group to move in accordance with an operating amount of the first external operating member for adjusting the flange back length; a macro-shooting controller for outputting the second electric signal instructing the master lens group to move in accordance with an operating amount of the second external operating member for setting of the macro-shooting; a switching means for validating one of the flange back length controller and the macro-shooting controller; a driving means for driving the master lens group; and a control means for outputting a drive signal to the driving means to drive the master lens group in accordance with the one of the first and second electric signals output from the one of the flange back length controller and the macro-shooting controller which is validated by the switching means.
According to the present invention, in order to adjust the flange back length by moving the master lens group, the switching means validates the flange back length controller, and the first external operating member of the flange back length controller is operated to move the master lens group to the position of the proper flange back length. Thereafter, during the macro-shooting or the shooting aiming to achieve special effects, the switching means validates the macro-shooting controller, and the second external operating member of the macro-shooting controller is operated to move the master lens group to the macro-shooting position or any other desired positions. In this case, the flange back length controller retains the instruction which was given to set the master lens group at the position of the proper flange back length. Thus, after the macro-shooting or the shooting aiming to achieve special effects is complete and the flange back length controller is validated again by means of the switching means, the flange back length controller outputs the instruction to move the master lens group to the previously-adjusted position of the proper flange back length, and the master lens group can return to the position of the proper flange back length.
Thus, the user can easily adjust the flange back length and perform the macro-shooting. After the macro-shooting, the master lens group can be correctly and repeatedly returned to the position of the proper flange back length, which was once adjusted. The macro-shooting controller moves the master lens group after the flange back length adjustment, so that the master lens group can smoothly move along the optical axis. It is advantageous for a special technique of naturally obscuring an image during the shooting.
Moreover, because the zoom operation of the TV camera lens is usually rate-controlled, the zoom controller as a control means for the zoom operation serves as the macro-shooting controller. There is provided the second switching means (a zoom/macro switching means) which determines whether the controller should be used as the zoom controller or as the macro-shooting controller. For this reason, no additional controller is required, and the operation can be easily performed with the existing external operating member.
Further, since the operating amount of the first and second external operating members is electrically converted into electric signals driving the master lens group, the ratio of the moving amount of the master lens group to the operating amount of the operating member can be electrically adjusted. Thus, if the sensitivity adjustment means changes the ratio of the moving amount to the operating amount, one external operating member can roughly and finely adjust the position of the master lens group.
Furthermore, the relationship between the operating direction of the operating member and the moving direction of the master lens group can be easily changed according to the electric connection. Since there is provided the reverse means, which reverses the moving direction of the master lens group with respect to the operating direction of the operating member, the directional relationship can be determined as the user's choice.
REFERENCES:
patent: 5523784 (1996-06-01), Nagano
patent: 5771410 (1998-06-01), Sato et al.
patent: 58-1401 (1983-01-01), None
patent: 60-46405 (1985-10-01), None
Kawamura Hiroyuki
Mizumura Hiroshi
Fuji Photo Optical Co., Ltd.
Ho Tuan
Nixon & Peabody LLP
Safran David S.
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