KR200216621Y1 - Ading photography apparatus for video camera lens unit - Google Patents

Abstract

Disclosed is a macro shooting apparatus for a video camera lens unit capable of selectively positioning a transparent plate on an optical path to adjust a focal length.

The apparatus comprises: a first lens group sequentially positioned from an object side toward an image surface, the first lens group having positive refractive power and fixedly disposed on an optical path; A second lens group movably disposed on the optical path to vary the magnification; A third lens group having positive refractive power and fixedly disposed on the optical path; A fourth lens group movably disposed on the optical path to adjust the magnification and focusing; A filter adapted to correct chromatic aberration; And a transparent plate selectively disposed between the filter and the top surface to move the focus position; It characterized in that it comprises a switching means for switching the transparent plate so that the transparent plate is disposed on the optical path during macro shooting. Here, the switching means may include a rotating plate rotatably disposed between the first to fourth lens groups and the first barrel surrounding the filter and the second barrel surrounding the image and fixedly installed with the transparent plate; And a driving unit installed in the first and second barrels and having a rotation shaft coupled to the rotating plate to rotate the rotating plate.

Description

Photographing apparatus for video camera lens unit {Ad apartment photography photography apparatus for video camera lens unit}

The present invention relates to a macro shooting device for a video camera lens unit, and more particularly, to a macro shooting device for a video camera lens unit to be able to adjust the focal length by selectively positioning the transparent plate on the optical path.

In general, a video camera lens unit is composed of a variable zoom lens unit, and is employed in a physical imager, a video camera, a still camera, and the like.

1 is a view illustrating an optical arrangement of a general internally focused video camera lens unit.

As shown, the lens unit and the filter 12 are constituted by 11 groups of 4 elements between the object 10 and the upper surface 14. The first lens group I and the third lens group III are fixedly installed on the optical path, and have a positive refractive power. The second lens group II is a lens group movably disposed between the first lens group I and the third lens group III to cause shifting. The fourth lens group IV is movably disposed between the third lens group III and the filter 12 to perform shifting and focusing.

The video camera lens unit configured as described above has a macro lens 20 having a positive refractive power between the first lens group I and the object 10 when the object distance is shortened within the focal length. Add) to focus. Here, if the object distance is shorter than the focal length of the video camera lens unit, a macro lens having a larger amount of refractive power is required. In this case, there is a disadvantage in that the aberration characteristics of the macro lens become worse.

In addition, it is difficult for the user to implement the auto focus function by manually mounting and releasing the macro lens unit.

The present invention has been made in view of the above-described point, and an object thereof is to provide a macro shooting device for a video camera lens unit capable of performing focusing by selectively placing a transparent plate on an optical path.

1 is a view showing an optical arrangement of a typical video camera lens unit.

2 shows an optical arrangement of a typical video camera lens unit with a macro lens unit.

3 is a view showing an optical arrangement of a video camera lens unit having a transparent plate according to an embodiment of the present invention.

4 and 5 are a perspective view showing a macro shooting device for a video camera lens unit according to an embodiment of the present invention.

<Description of the reference numerals for the main parts of the drawings>

Ⅰ ... 1st lens group Ⅱ ... 2nd lens group Ⅲ ... 3rd lens group

IV lens group 10 object 12 filter

14 ... top 31 ... transparent plate 33 ... turning plate

35 Driving part 35a Rotating shaft 41

43 ... 2nd barrel

In order to achieve the above object, the present invention, the first lens group having a positive refractive power and fixedly disposed on the optical path from the object side toward the image surface; A second lens group movably disposed on the optical path to vary the magnification; A third lens group having positive refractive power and fixedly disposed on the optical path; A fourth lens group movably disposed on the optical path to adjust the magnification and focusing; A filter adapted to correct chromatic aberration; A macro shooting device for a video camera lens unit, comprising: a transparent plate selectively disposed between the filter and an upper surface to move a focus position; It characterized in that it comprises a switching means for switching the transparent plate so that the transparent plate is disposed on the optical path during macro shooting.

Preferably, the switching means comprises a rotating plate rotatably disposed between the first to fourth lens group and the first barrel surrounding the filter and the second barrel surrounding the upper surface and fixed to the transparent plate; And a driving unit installed in the first and second barrels and having a rotating shaft coupled to the rotating plate to rotate the rotating plate.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Referring to FIG. 3, the video camera lens unit includes 11 lens units of 4 groups on the optical path between the object 10 and the image surface 14, and a filter 12. That is, the first lens group I and the third lens group III have positive refractive power and are fixedly disposed on the optical path. The second lens group II is movably disposed between the first and third lens groups I and III to vary the magnification. The fourth lens group IV is movably disposed on the optical path between the third lens group III and the filter 12 to adjust the variable magnification and the focusing. The filter 12 corrects chromatic aberration.

The macro shooting device 30 of the present invention is selectively disposed between the filter 12 and the upper surface 14 to move the focus position so that the macro shooting can be performed at the time of shooting using the video camera lens unit configured as described above. A transparent plate 31 and switching means for switching the transparent plate 31 are provided.

In this case, when the transparent plate 31 is disposed on the optical path, the focal position moves as much as shown in Equation (1).

here, Is the focal length shift, Is the refractive index of the transparent plate, Is the thickness of the transparent plate.

Therefore, by changing the transparent plate 31, the focus position of the video camera lens unit can be changed, so that macro photography is possible.

4 and 5, the switching means includes a rotating plate 33 on which the transparent plate is fixed and a driving unit 35 for driving the rotating plate 33. The rotating plate 33 is rotatably disposed between the first barrel 41 surrounding the first to fourth lens groups and the filter 12 and the second barrel 43 surrounding the upper surface 14. The driving unit 35 has a rotating shaft 35a coupled to the rotating plate 33, and is installed in the first and second barrels 41 and 43.

Therefore, during macro shooting, as shown in FIG. 4, the rotating plate 33 is rotated by the driving of the driving unit 35 so that the transparent plate 31 is disposed on the optical path. On the other hand, when the object distance is located farther than the focal length, the transparent plate 31 is disposed in a position off the optical path by rotating the rotating plate 33 by the drive unit 35, as shown in FIG.

The driving unit 35 may be operated by a user's manipulation button as well as automatically by a separate sensor capable of measuring a distance.

As described above, the macro shooting device for a video camera lens unit according to the present invention is configured to allow macro shooting by selectively placing a transparent plate having a predetermined thickness on an optical path, and also to drive the transparent plate. Can be implemented automatically as well as manual, so that the auto focus can be extended to the macro shooting range.

Claims (2)

From the object side to the upper surface sequentially, A first lens group having positive refractive power and fixedly disposed on the optical path; A second lens group movably disposed on the optical path to vary the magnification; A third lens group having positive refractive power and fixedly disposed on the optical path; A fourth lens group movably disposed on the optical path to adjust the magnification and focusing; A filter adapted to correct chromatic aberration; In the macro shooting device for a video camera lens unit, A transparent plate selectively disposed between the filter and the top surface to move a focus position; And a switching means for switching the transparent plate so that the transparent plate is disposed on the optical path during macro shooting. The method of claim 1, wherein the switching means, A rotating plate rotatably disposed between the first and fourth lens groups and the first barrel surrounding the filter and the second barrel surrounding the image surface, the rotating plate being fixed to the transparent plate; And a driving unit installed on the first and second barrels and having a rotating shaft coupled to the rotating plate to rotate the rotating plate.