KR0133642B1 - Manual focusing apparatus for camcorder - Google Patents

Abstract

The present invention relates to a manual focusing apparatus of a camcorder, which enables manual focusing while visually checking the degree of focusing on an image pickup tube, which is impossible with the optical viewfinder of a general camcorder.

As described above, the present invention provides beam dividing means for dividing an optical signal of a subject obtained from a zoom lens into an image forming section and a viewfinder side, a focus plate means positioned on an image forming surface of light separated from the beam dividing means to a viewfinder side, and the focus point. A reflection means for changing the optical path of the image formed on the plate means and an eyepiece means for visually seeing the image formed on the focus plate means from the reflection means.

Description

Manual focus control on the camcorder

1 is a schematic view of a viewfinder of a conventional camcorder, (a) is a cathode ray tube viewfinder configuration, and (B) is an image pickup tube (CCD) viewfinder configuration.

2 is a view of the optical viewfinder of a conventional simple cam.

3 is a block diagram of a manual focus control device of the camcorder of the present invention.

4 is an enlarged view showing in detail the focus plate means of FIG.

5 is a view for explaining the focus plate means of FIG.

6 is a state of focus confirmation according to FIG.

7 is a configuration of another embodiment of the manual focusing apparatus of the camcorder of the present invention.

9 is a configuration diagram of another embodiment of the present invention without the reflector of FIG.

* Explanation of symbols for main parts of the drawings

100 zoom lens 101 beam splitting means

102: focusing plate means 103: reflecting means

104: eyepiece means 105: imaging tube

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical viewfinder in a camera-integrated BD (hereinafter, referred to as a camcorder), and in particular, a camcorder that enables manual focusing while visually checking the degree of manual focusing, which is impossible with an optical viewfinder of a general camcorder. To a manual focus control device.

In general, a viewfinder applied to a camcorder is configured to reconstruct an image of a subject in an imaging tube (CCD) using a tube or a liquid crystal display device (LCD), and to observe this through a viewfinder lens.

The viewfinder of such a conventional camcorder can be divided into a cathode ray tube type viewfinder, an image pickup tube type viewfinder, and an optical viewfinder of a simple cam.

The schematic structure of the former cathode ray tube viewfinder is, as shown in FIG. 1A of the accompanying drawings, an image forming unit 2 made of a cathode ray tube displaying an image of a subject, and the image forming unit ( It consists of an alternative lens (EYE PIECE) (1) that can see the image of the subject displayed in 2) when the image of the subject to be taken is formed in the image forming unit (2) to see the image of the subject through the alternative lens (1) It is supposed to be.

The latter image pickup tubular viewfinder includes an image forming unit 11 made of a liquid crystal display element (LCD) for displaying an image of a subject, as shown in FIG. And a lamp 12 for illuminating the light to display the image of the subject, and an alternative lens 10 for viewing the image of the subject formed in the image forming unit 11. When the image of the subject is formed in the), the image of the subject can be viewed through the alternative lens 10.

On the other hand, an example of the optical viewfinder applied to the camcorder can be seen in the current simple cam, as shown in FIG.

At this time, the optical viewfinder 20 is a separate zoom lens equipped with an alternative lens so as to be visible to the eye at all apart from the zoom lens 21 of the camcorder. That is, as shown in FIG. 2, the image of the subject through the zoom lens 21 is formed in the image pickup tube 22, and the image of the subject can be viewed through the alternative lens of the separate optical viewfinder 20.

However, the viewfinder of such a conventional camcorder has a limitation in lowering the cost of the camcorder set because the unit price of the image component itself is expensive when the viewfinder is constructed using a cathode ray tube tube or an image component such as a liquid crystal display unit. Because of the high power consumption of the picture elements, the camcorder takes a short time to shoot.

In order to make up for this drawback, an optical viewfinder was devised, but when the LS method, which is a camera viewfinder method, was used, the zoom lens of the camcorder and the optical viewfinder lens are separate, so the image observed by the eyes and the actual photographed image are slightly different. There is also a difference, and it is not possible to determine whether the focusing of the image being photographed is correct, and there is a problem in that manual focusing is not possible.

On the other hand, SLR (SING LENS REFLEX), which is a viewfinder of a general camera, is used for focusing with a matte surface such as glass or a split image prism focused on the eye. It is possible to check the fit situation, but these methods have a problem that cannot be applied to the camcorder due to the discrimination problem in the case of the mat surface and the brightness problem in the case of the split prism.

Accordingly, an object of the present invention is to provide a manual focusing apparatus of a camcorder to enable manual focusing while visually checking the degree of focusing in the image pickup tube, which is impossible with the optical viewfinder of a general camcorder.

As a means for achieving the object of the present invention, the beam splitting means for dividing the optical signal of the subject obtained from the zoom lens to the image forming portion and the viewfinder side, and the image plane of the light separated from the beam dividing means to the viewfinder side A focus plate means located in the, the reflecting means for changing the optical path of the image formed on the focus plate means, and the eyepiece means for visually seeing the image formed in the focus plate means from the reflecting means Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. 3 is a configuration diagram of a manual focus control device of a camcorder according to the present invention, as shown in FIG. A beam splitter 101 for dividing an optical signal of the photographed subject into an image forming unit and a viewfinder, and an image of a subject located at an image plane of light separated from the beam splitting unit 101 to the viewfinder; The focus plate means 102, the reflecting means 103 for changing the optical path of the image formed on the focus plate means 102, and the image formed on the focus plate means 102 from the reflecting means 103. And an eyepiece means 104 made of a lens system and a imaging tube 105 which is an image forming body for converting light of a subject divided by the beam splitting means 101 into a captured image signal.

First, when the optical signal of the subject is enlarged and reduced through the zoom lens 100 according to the zoom ratio, the beam splitter 101 splits the beam of light entering through the zoom lens 100 into two.

As shown in FIG. 4 of FIG. 4 divided by the beam dividing means 101, an image is formed on the image plane AA of the imaging tube 105, and the other light is imaged on the mat surface 102a of the focus plate means 102. FIG. In addition, it is reflected to the eyepiece means 104 through the reflecting means 103.

That is, the distance from the middle point P to A'-A 'of the beam splitter 101 is equal to the distance from the middle point P to the image plane A-A.

The focusing plate means 102 is composed of a flat mat surface 102a which is spaced from one side by the distance d toward the optical viewfinder and one side by the distance d toward the center of the prism.

The distance d at this time can be represented by the following equation.

d = (t-δ) / 2

In this case, t is the indistinguishable distance of the mat surface used, and δ is the depth of focus of the zoom lens 100.

The meaning of the above formula is the same as in FIG.

That is, the stages of the indistinguishable positions of the two mat surfaces 102a of the focus plate means 102 are staggered with the difference of the depth of focus of the zoom lens 100 centered on the imaging position of the zoom lens 100 of the camcorder. will be.

In this case, looking at the focusing plate means 102 through the eyepiece means 104, the left and right objects are vividly clear at the same time when the imaging position is within a region where there is no problem in photographing with the imaging tube 105, that is, the depth of focus of the zoom lens 100. If it is visible, but it is out of the area, only one of them appears clearly as shown in FIG.

As an example, in the case of a zoom lens system having a focal depth of 50 μm (δ), the distance d is as follows when using a matt surface 102a having a non-distinguishable distance of 150 μm (t).

d = (150-150) / 2 = 50 (μm) so that the left and right objects are clearly visible.

7 is a configuration diagram of another embodiment of the focus plate means. Here, the focus plate means 102 may be divided into several parts instead of two parts to implement the same performance.

As an example, as shown in FIG. 7, it can be divided into three, four, or many surfaces while having the same surface as the mat surface 102a of the focus plate means 102.

The performance at this time is also the same as that in FIG.

In addition, as shown in FIG. 9 without the reflecting means 103 of FIG. 3, the same performance may be achieved by connecting the eyepiece means 104 or separating the focus plate means 102 from the beam splitting means 102.

The same performance can be realized by using the focusing plate means 102 on the portion of the image formed on the image forming surface using the relay lens 106 to reimage.

As described in detail above, according to the present invention, since the unit cost of the product is not reduced due to the use of expensive image elements, and the power consumption of the viewfinder is little, the camcorder recording time Compared to the simple viewfinder's optical viewfinder, the shot image and the viewfinder observation image match, making it easy to compose the screen and visually confirming the degree of focusing to the imager. Not only can this be customized, but the viewfinder for camcorders is mainly used, and it can be applied to viewfinders of various optical systems including general cameras.

Claims (7)

A focus adjustment apparatus of a camcorder, comprising: beam dividing means for dividing light of a subject obtained from a zoom lens into an image forming portion and a viewfinder side of an image pickup tube, and a beam dividing means integrally with the beam dividing means, Focus plate means composed of a combination of planes that can be manually adjusted by the user while looking at the eyes, reflecting means for changing the optical path of the image formed on the focus plate means, and the image formed on the focus plate means Manual focusing device of a camcorder comprising an eyepiece means for viewing an image visually. The apparatus of claim 1, wherein the plane of the focusing plate means is disposed above and below the image forming surface. The apparatus of claim 1, wherein the plane of the focusing plate means is disposed above and below the image forming surface. The apparatus of claim 2, wherein the plane of the focusing plate means is located at a distance satisfying (t-δ). t: Inability to discriminate the mat plane, δ: Depth of focus of the imaging lens. The apparatus of claim 1, wherein an image formed from the focus plate means is directly transferred to the eyepiece means. The apparatus of claim 1, wherein the focus plate means is located between the reflecting means and the eyepiece means. 7. A manual focusing apparatus for a camcorder according to claim 6, wherein a relay lens is employed between the reflecting means and the focusing plate means.