JPH10268175A - Zoom lens device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of a ghost when a variable-power lens and correcting lens are located most apart by providing shielding members shielding the notches of the moving frames of a lens support frame on the lens support frame of the variable-power lens toward the rear of the optical axis. SOLUTION: Shielding plates 40 shielding the notches of the moving frames 23 of a lens support frame 22 are protrusively formed on the lens support frame 22 of a variable-power lens 14 toward the rear of the optical axis. The shielding plates 40 are formed at nearly the same length as that of the moving frames 23 at the positions not interfering with the moving frames 25 of a correcting lens 16 side at the TELE position. When the variable-power lens 14 is located at the position (WIDE end) most apart from the correcting lens 16, the harmful light within the light passing through a focus lens 12 is shielded by the shielding plates 40 and is not fed to the correcting lens 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a zoom lens device, and more particularly to a zoom lens device for a television camera capable of photographing at a high magnification.

[0002]

2. Description of the Related Art In a zoom lens apparatus having a variable power lens and a correction lens, it is necessary to set a long zoom movement range of the variable power lens and the correction lens in order to photograph at higher magnification. Therefore, the moving frame of the variable power lens,
Since the moving frame of the correction lens may interfere when it moves to the closest position, each moving frame is formed with a plurality of notches, and the moving frame of the other party is escaped in the notch. Interference between moving frames is prevented.

[0003]

However, in the conventional zoom lens apparatus, when the variable power lens is located at a position farthest from the correction lens, harmful light from the front of the variable power lens is displaced between the moving frames of the variable power lens. Since the light enters the correction lens through the notch, there is a disadvantage that a ghost occurs.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a zoom lens device which can prevent the occurrence of ghost when the variable power lens and the correction lens are farthest from each other. And

[0005]

In order to achieve the above object, the present invention provides a zoom lens apparatus having a variable power lens and a correction lens, wherein the zoom lens apparatus is provided with a lens extending from a lens support frame of the variable power lens in an optical axis direction. A moving frame partially cut away is provided, and a moving frame partially cut away from the lens support frame of the correction lens in the optical axis direction is provided. The movable frame of the lens is formed so as to directly enter the notch on the other side, and the lens support frame of the variable power lens is provided with a light shielding member for shielding the notch of the movable frame of the lens support frame. It is characterized by being provided toward the rear of the axis.

According to the first aspect of the present invention, the lens supporting frame of the variable power lens is provided with a light shielding member for blocking the notch of the moving frame of the lens supporting frame toward the rear side of the optical axis. Light incidence can be prevented. Therefore, the present invention can prevent the occurrence of ghost. By the way, it is conceivable to provide a donut-shaped light shielding plate on the entire surface of the lens support frame of the variable power lens in place of the light shielding member.
However, when the light-shielding plate is fixed at that position, a part of the lens support frame of the correction lens hits the light-shielding plate when the variable power lens and the correction lens come close to each other, and it becomes impossible to approach the same over a certain distance. The problem described above occurs. Therefore, according to the present invention, the light blocking member is provided in the optical axis direction, and the distance between the lens support frame of the variable power lens and the lens support frame of the correction lens can be made as close as possible.

According to a second aspect of the present invention, an opening is formed in the lens support frame of the correction lens so that the light-blocking member of the variable power lens enters. Accordingly, in the present invention, even when the variable power lens and the correction lens come close to each other, the light blocking member and the lens support frame of the correction lens do not interfere. Therefore, the length of the light shielding member can be sufficiently set, so that the light shielding property is improved.
Further, since the zoom movement range of the variable power lens and the correction lens can be set longer, a zoom lens device with higher magnification can be provided.

According to the third aspect of the present invention, the lens support frame of the variable power lens and the lens support frame of the correction lens are connected by a cylindrical flexible light shielding member, and the lens support frame of the variable power lens is provided. Since the notch of the moving frame is shielded by the light shielding member, ghost can be prevented from occurring.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a zoom lens device according to the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a sectional view of a zoom lens device 10 for a television camera to which the zoom lens device according to the present invention is applied. In the zoom lens device 10 shown in FIG. 1, a focus lens 12, a variable power lens 14, a correction lens 16, and a master lens 18 are arranged in this order from the front with respect to the optical axis L. Further, in the zoom lens device 10, the focus lens 12 is large in order to realize a wider-angle shooting,
In addition, a variable power lens 1 to realize higher magnification shooting
4, and the zoom movement range of the correction lens 16 is set long.

The focus lens 12 is disposed in the large-diameter opening at the front end of the lens barrel 20, is provided so as to be movable back and forth along the optical axis L, and is moved back and forth by a driving device (not shown). Thus, focus adjustment is performed.
The variable power lens 14 is supported by a lens frame 22, and the correction lens 16 is also supported by a lens frame 24. A pin 26 is implanted in the lens frame 22, and the pin 26 is engaged with a variable lens cam groove 30 of a cam cylinder 28 through a slit 27 formed in a lens barrel. Similarly, a pin 32 indicated by a two-dot chain line is implanted in the lens frame 24 of the correction lens 16, and the pin 32 is engaged with the correction lens cam groove 34 of the cam cylinder 28 through the slit 27. Have been combined. The cam cylinder 28 has a motor 36
Are connected to the output shaft 38. Therefore, the cam cylinder 2
When the motor 8 is rotated forward / reverse by the driving force of the motor 36, the variable power lens 14 moves back and forth in the optical axis L direction along the locus of the cam groove 30. Similarly, the correction lens 16 moves back and forth in the optical axis L direction along the locus of the cam groove 34. Since the variable power lens 14 and the correction lens 16 have positive power, WIDE shooting can be performed at the position where the variable power lens 14 and the correction lens 16 are farthest from each other (see FIGS. In the position shown in FIG.
ELE photography is possible.

Incidentally, the variable power lens 14 and the correction lens 1
The zoom movement range of the zoom lens 6 is set to be long in order to enable higher magnification photographing as described above. For this reason, the moving frame 23 of the lens frame 22 of the variable power lens 14 and the moving frame 25 of the lens frame 24 of the correction lens 16 may interfere when moved to the closest position. Each of the moving frames 23 and 25 is formed with a plurality of notches as shown in FIG.
3 and 25 are released as shown in FIG.
Interference between 3, 25 is prevented. However, if the variable power lens 14 is located at the position farthest from the correction lens 16 (see FIGS. 1 and 2), the harmful light L1 of the light that has passed through the large focus lens 12 is changed to the variable power lens. The light enters the correction lens 16 through the notch between the 14 moving frames 23, 23, 23, and a ghost occurs.

Therefore, in this embodiment, as shown in FIG. 2, the lens support frame 22 of the variable power lens 14 is provided with three light shielding plates for blocking the notches of the moving frames 23, 23, 23 of the lens support frame 22. The plates 40, 40, and 40 are formed so as to protrude rearward of the optical axis to prevent incidence of the harmful light L1. These light shielding plates 40, 40, 40 are formed to have substantially the same length as the moving frame 23, and are formed at positions that do not interfere with the moving frames 25, 25, 25 on the correction lens 16 side at the TELE position shown in FIG. Have been. Also, at the TELE position,
Three slits 42, 42, 42 are opened in the lens support frame 24 so that the tip 41 of the light shielding plates 40, 40, 40 does not interfere with the lens support frame 24 of the correction lens 16 (FIG. 2). 2 and 3 schematically show the positional relationship between the variable power lens 14 and the correction lens 16 at WIDE end and TELE end positions.

Next, the operation of the zoom lens device 10 configured as described above will be described. First, zoom lens 1
4 and the correction lens 16 are moved in the WIDE direction,
When located at the WIDE end (see FIG. 1), the harmful light L1 of the light passing through the focus lens 12 is
The light is blocked at 0, 40, and 40 and does not enter the correction lens 16. Therefore, ghost can be prevented from occurring at the WIDE end position.

Next, the variable power lens 14 and the correction lens 16 are moved in the TELE direction.
The light enters the variable power lens 14 without being blocked by zero. As described above, in the present embodiment, by providing the light shielding plate 40, it is possible to prevent the occurrence of a ghost at the WIDE end position, and to perform the photographing at the TELE end position without any trouble.

In the present embodiment, the correction lens 16
Since the slits 42, 42, 42 into which the light shielding plates 40, 40, 40 enter are formed in the lens support frame 24, even if the variable power lens 14 and the correction lens 16 come close to each other, the light shielding plate 40 The lens support frame 24 of the lens 16 does not interfere. Therefore, the length of the light shielding plate 40 can be sufficiently set, so that the light shielding property is improved. Also, a variable power lens 1
4 and the zoom movement range of the correction lens 16 can be set longer, so that the zoom lens device 1 with higher magnification
0 can be provided.

FIG. 4 is a sectional view of a zoom lens apparatus 50 according to a second embodiment of the present invention, in which the variable power lens 14 and the correction lens 16 are located on the WIDE side. In the description of the second embodiment, the same or similar members as those of the first embodiment shown in FIGS. 1 to 3 are denoted by the same reference numerals, and description thereof will be omitted.

In the second embodiment, the lens support frame 22 of the variable power lens 14 and the lens support frame 24 of the correction lens 16 are connected by a cylindrical bellows (flexible light-shielding member) 52 to change the magnification. Moving frame 23 of lens support frame 22 of lens 14,
The cutouts 23 and 23 are shielded by bellows 52. The bellows 52 is, for example, a black color that can absorb light. Therefore, the harmful light L1 entering from the notch is shielded by the bellows 52, so that the occurrence of ghost can be prevented.

In this embodiment, since the bellows 52 which can be extended and contracted in the direction of the optical axis L is applied, the zoom movement of the variable power lens 14 and the correction lens 16 is not affected at all.
Further, in the present embodiment, the bellows 52 is applied as the flexible member. However, the present invention is not limited to this, and any flexible member that is cylindrical and has a light shielding property and does not hinder zoom movement may be used. The form does not matter.

In this embodiment, the zoom lens device 10 applied to a television camera has been described. However, the zoom lens device 10 may be applied to a general camera using a photographic film.

[0020]

As described above, according to the zoom lens apparatus of the present invention, a light-blocking member for blocking the notch of the moving frame of the lens supporting frame is provided on the lens supporting frame of the variable power lens behind the optical axis. Since it is provided facing, it is possible to prevent the occurrence of ghost. According to the zoom lens device of the present invention, the lens support frame of the variable power lens and the lens support frame of the correction lens are connected by a cylindrical flexible light shielding member, and the lens support frame of the variable power lens is Since the notch of the moving frame is shielded by the flexible light shielding member, ghost can be prevented from occurring.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of a zoom lens device for a television camera to which a zoom lens device according to the present invention is applied.

FIG. 2 is a perspective view when each lens of the zoom lens device shown in FIG. 1 is located at a wide end.

FIG. 3 is a perspective view when each lens of the zoom lens device shown in FIG. 1 is located at a telephoto end;

FIG. 4 is a sectional view showing a second embodiment of the zoom lens device according to the present invention;

[Explanation of symbols]

 10, 50: Zoom lens device 12: Focus lens 14: Variable magnification lens 16: Correction lens 20: Lens barrel 23, 25: Moving frame 40: Light shielding plate 42: Slit 52: Bellows

Claims (3)

[Claims] 1. A zoom lens device comprising a variable power lens and a correction lens, wherein a moving frame partially cut away from a lens support frame of the variable power lens in an optical axis direction is provided. A moving frame partially cut away from the lens support frame of the correction lens in the optical axis direction is provided, and the moving frame of the variable power lens and the moving frame of the correction lens are directly cut out from each other on the other side. A zoom lens, which is formed so as to penetrate, wherein a light-blocking member that shields a notch of a moving frame of the lens supporting frame is provided toward a rear side of an optical axis in a lens supporting frame of the variable power lens. apparatus. 2. The lens support frame of the correction lens is provided with an opening through which the light-blocking member of the variable power lens enters when the variable power lens and the correction lens approach each other. Item 2. The zoom lens device according to item 1. 3. A zoom lens device comprising a variable power lens and a correction lens, wherein a moving frame partially cut away from a lens support frame of the variable power lens in an optical axis direction is provided. A moving frame partially cut away from the lens support frame of the correction lens in the optical axis direction is provided, and the moving frame of the variable power lens and the moving frame of the correction lens are directly cut out from each other on the other side. The lens support frame of the variable power lens and the lens support frame of the correction lens are connected by a cylindrical flexible light shielding member, and the notch of the movable frame of the variable power lens is A zoom lens device, wherein the zoom lens device is shielded by an opaque light shielding member.