JP3372153B2 - Ghost light regulator for video cameras - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ghost light restricting portion for restricting harmful ghost light incident through an image pickup lens group at the time of photographing an object, in front of a portion where an optical low pass filter is mounted in a camera barrel. The present invention relates to a ghost light restricting portion of a video camera which is integrally provided in a mask shape with a lens barrel.

[0002]

2. Description of the Related Art Generally, a video camera such as a magnetic recording / reproducing apparatus with a built-in camera can record an object photographed by a photographing lens on a magnetic tape by a VTR provided inside.
In addition, it is compact and lightweight and has good portability.

FIG. 4 is a perspective view showing a general video camera, and FIG. 5 is a view showing a state in which the influence of ghost light appears in the lower part of the screen when a subject is photographed with the general video camera. Is.

When the subject H is photographed outdoors using the general video camera 1 as shown in FIG. 4, the subject H is photographed by inserting sunlight S or the like in the screen as shown in FIG. Then, since the ghost light G, which is unnecessary noise light, is emitted from the sunlight S in a shower shape, the ghost light G may appear in the lower part of the screen on which the subject H is photographed.
This ghost light G may make the screen very unsightly. The above-mentioned ghost light G is noise light that is generally unnecessary for a target image.

[0005]

By the way, as a method of preventing the influence of the ghost light G on the screen when the video camera 1 is used, a hood is attached in front of the taking lens, or the transmittance of the taking lens is increased. And a coating for reducing reflection is provided, or a mask for shielding ghost light is separately installed in front of the image pickup device in the video camera 1.

However, as described above,
When the hood is attached in front of the taking lens, the influence of the ghost light G can be reduced, but it hinders the downsizing and weight saving of the video camera 1, and accordingly, when the hood is not always used when carrying, the ghost light G The influence of G comes out.

Further, as described above, when the photographing lens is coated with a film for reducing the influence of the ghost light G, it is good for the ghost light G, but
The cost of coating the film is added, and the taking lens becomes expensive.

Further, as described above, when a mask for shielding ghost light is separately installed in front of the image pickup device, the number of parts is increased and a space for installing the mask is provided in front of the image pickup device. Must be secured.

Therefore, there is a demand for a ghost light restricting portion of a video camera which can be achieved with a simple structure without causing the influence of ghost light on the screen when photographing a subject.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and provides an image pickup lens group for taking an image of a subject and a pseudo signal by a high frequency component of an image of the subject taken by the image pickup lens group. In a video camera in which an optical low-pass filter for preventing and an image sensor for photoelectrically converting a subject image that has passed through the optical low-pass filter are arranged in the above order with their optical axes aligned in the camera barrel, the incidence of the optical low-pass filter
It is installed just before the surface and goes integrally with the camera barrel.
A strobe light control unit is provided, and
To prevent light from entering the optical low-pass filter.
A ghost light regulating unit of the video camera, characterized by being configured to so that.

Further, in the ghost light restricting portion of the video camera of the above invention, the ghost light restricting portion has a narrow opening on the incident side of the ghost light along the outer side of the optical low-pass filter, and has an exit side on the exit side. A ghost light restricting portion of a video camera, characterized in that the ghost light restricting portion is formed on a knife edge surface that is wide and obliquely opened toward the optical low-pass filter side.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a ghost light regulating section of a video camera according to the present invention will be described in detail below with reference to FIGS.

FIG. 1 is a cross-sectional view showing a configuration inside a camera barrel of a video camera for explaining a ghost light regulating portion of the video camera according to the present invention, and FIGS. 2 (A) and 2 (B) are the same video. In order to explain the ghost light restricting portion of the camera, a sectional view showing a camera barrel of the video camera, a right side view, and FIG. 3 are schematic views for explaining the operation of the ghost light restricting portion of the video camera. .

As shown in FIG. 1, the video camera 1 includes an imaging lens group 10 (11 to 14) for photographing a subject H,
An optical low-pass filter 20 that prevents a false signal due to a high-frequency component of a subject image captured by the imaging lens group 10 and an image sensor 22 that photoelectrically converts the subject image that has passed through the optical low-pass filter 20 are emitted into the camera barrel 2. The axes K are aligned and arranged in the above order.

The image pickup lens group 10 includes an image pickup lens 11 fixed in front of the camera barrel 2 on the subject H side, and a zoom movable in the optical axis direction inside the camera barrel 2 behind the image pickup lens 11. It includes a lens 12, a fixed master lens 13 fixed behind the zoom lens 12, and a focus lens 14 that is movable in the optical axis direction inside the camera barrel 2 behind the fixed master lens 13.

An optical low-pass filter 20 is fixedly provided behind the focus lens 14 in the camera barrel 2. The optical low-pass filter 20 is inserted from the rear surface 2c side which opens the rear portion of the camera barrel 2 and is fixed to the portion 2b provided in the camera barrel 2 to which the optical low-pass filter 20 is attached. Further, in front of the portion 2b to which the optical low-pass filter 20 is attached, a ghost light restricting portion 2a, which will be described later, which is a main part of the present invention, is formed. The optical low-pass filter 20 is provided to prevent a false signal due to a high frequency component of a subject image captured by the imaging lens group 10.

Further, an image pickup element 22 is fixedly provided behind the optical low-pass filter 20 via a rubber 21. The image pickup device 22 includes a support plate 23 made of an adhesive or the like.
Is fixed in advance to the optical low-pass filter 2 from the rear surface 2c side through the rubber 21 in this state.
After pressing to the 0 side, the support plate 23 is supported on the rear surface 2c of the camera barrel 2. Then, the subject image photographed by the image pickup lens group 10 is formed on the image pickup device 22 after passing through the optical low-pass filter 20, and the image pickup device 2 is formed.
The subject image is photoelectrically converted by 2.

Here, the ghost light restricting portion of the video camera, which is an essential part of the present invention, will be described with reference to FIGS.

The ghost light restricting portion of the video camera, which is an essential part of the present invention, controls the harmful ghost light G (FIG. 3) incident through the image pickup lens group 10 when the subject is photographed. Is provided in a substantially rectangular mask shape integrally with the camera barrel 2 in front of the portion 2b in the camera barrel 2 where the optical low-pass filter 20 is attached.

That is, the ghost light restricting portion 2a provided in the camera barrel 2 has a substantially rectangular shape along the outside of the optical low-pass filter 20 so that the object image photographed by the imaging lens group 10 can reach the optical low-pass filter 20. Of the mask shape, the incident side of the ghost light G is narrowly opened, and the emitting side thereof is the optical low-pass filter 2.
Knife edge surface 2a that is wide open diagonally toward the 0 side
₁ is formed.

Therefore, as shown in FIG. 3, the harmful ghost light G incident through the image pickup lens group 10 at the time of photographing the subject H is restricted by the mask-shaped ghost light restricting portion 2a formed in front of the optical low-pass filter 20. As a result, the ghost light G causes the optical low-pass filter 2
0 and the image sensor 22 can be prevented from being incident, and the subject image is well formed on the image sensor 22. At this time, the substantially rectangular mask-shaped ghost light restricting portion 2a has a narrow knife edge surface 2a ₁ that has a narrow opening on the incident side of the ghost light G and a wide opening obliquely on the emitting side toward the optical low-pass filter 20 side. Since the ghost light G is formed on the knife edge surface 2a ₁ , the ghost light G is not diffusely reflected by the knife edge surface 2a ₁ , so that the ghost light G does not enter the optical low-pass filter 20.

A part of the ghost light G is reflected by the optical low-pass filter 20, and then the focus lens 14
However, the ghost light G reflected again is naturally also restricted by the ghost light restricting portion 2a.

In the embodiment, the ghost light regulating portion 2a
Has been described as being formed in a substantially rectangular mask shape along the outside of the optical low pass filter 20, but the invention is not limited to this, and the ghost light restricting portion 2a is formed only in the direction in which the ghost light G due to sunlight is likely to occur. May be, for example, FIG.
When the influence of the ghost light G is likely to appear on the lower side of the screen shown in (3), a method of forming the ghost light restricting portion 2a only in the corresponding direction portion may be considered.

[0024]

According to the ghost light regulation section of the video camera according to the present invention described in detail above, according to the first aspect, the ghost light regulation which controls harmful ghost light incident through the image pickup lens group at the time of photographing an object. This part is provided in a mask shape integrally with the camera barrel in front of the part where the optical low-pass filter is mounted inside the camera barrel, and as a result, ghost light is restricted by the ghost light regulation part formed in front of the optical low-pass filter. As a result, the ghost light can be prevented from entering the optical low-pass filter and the image pickup device, and the subject image is well formed on the image pickup device.

According to a second aspect of the present invention, in the ghost light restricting portion of the video camera according to the first aspect, the ghost light restricting portion has a narrow opening on the incident side of the ghost light along the outside of the optical low pass filter. Moreover, since the emission side is formed as a knife edge surface that is wide and obliquely opened toward the optical low pass filter side, as a result, the ghost light is not diffusely reflected by the knife edge surface, so that the ghost light does not enter the optical low pass filter. .

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a configuration inside a camera barrel of a video camera for explaining a ghost light restricting portion of the video camera according to the present invention.

2A and 2B are a sectional view and a right side view showing a camera barrel of a video camera for explaining a ghost light restricting portion of the video camera according to the present invention.

FIG. 3 is a schematic diagram for explaining the operation of the ghost light restricting section of the video camera according to the present invention.

FIG. 4 is a perspective view showing a general video camera.

FIG. 5 is a diagram showing a state in which the influence of ghost light appears in the lower part of the screen when a subject is photographed using a general video camera.

[Explanation of symbols]

1 ... video camera, 2 ... camera barrel, 2a ... ghost light regulating unit, 2a 1 _... knife edge surface, 2b ... portion for mounting the optical low-pass filter, 10 ... imaging lens group 11
... Imaging lens, 12 ... Zoom lens, 13 ... Fixed master lens, 14 ... Focus lens, 20 ... Optical low-pass filter, 22 ... Imaging element, H ... Subject, G ... Ghost light, K ... Optical axis.

─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Toshiya Endo 3-12 Moriya-cho, Kanagawa-ku, Yokohama, Kanagawa Japan Victor Company of Japan (72) Inventor Hideaki Muramatsu 3-12 Moriya-cho, Kanagawa-ku, Yokohama Within Victor Company of Japan (56) Reference JP 4-217184 (JP, A) JP 4-180478 (JP, A) JP 4-314273 (JP, A) (58) Fields investigated ( Int.Cl. ⁷ , DB name) H04N 5/225 G03B ^7/ 00-11/00

Claims (2)

(57) [Claims] 1. An image pickup lens group for photographing a subject, an optical low-pass filter for preventing a false signal due to a high-frequency component of a subject image photographed by the image pickup lens group, and a subject image passed through the optical low-pass filter are photoelectrically converted. In the video camera, in which the image pickup element and the image pickup element are arranged in the above order in the camera barrel so that the optical axes thereof are aligned with each other, the image pickup element is provided immediately before the entrance surface of the optical low-pass filter
Together with the camera barrel, a ghost light control unit was installed.
The ghost light that entered through the shooting lens group
To prevent it from entering the optical low pass filter
The ghost light control unit of the video camera, which is characterized by its construction . 2. The ghost light restricting portion of the video camera according to claim 1, wherein the ghost light restricting portion has a narrow opening on an incident side of the ghost light along an outer side of the optical low pass filter and an emitting side. Is formed on a knife edge surface that is wide and obliquely opened toward the optical low-pass filter side.