Filter for Cameras

Field of The Invention

The present Invention relates to opening and shutting device of the infrared-ray filter for cameras, which makes it possible to form clear images by selectively adjusting the amount of infrared ray absorbed into the photographic elements through the infrared-ray filter with a built-in opening-shutting device, the filter being set in the rear of the lens channel inside a camera.

1 0 Prior Art Relative To The Invention

Generally, the photographic elements in a camera work upon perception of visible rays and infrared ray, and when light passes through the lens of a camera the visible rays are separated into three colors via an R.G.B. filter, and reach the photographic elements

1 5 11 to form an image, while infrared ray untrammeled by the R.G.B. filter directly reaches the photographic elements 11 and affects them 11. If the infrared ray remains below a certain quantity, its influence on the photographic elements 11 in forming the color tone is not much, but at places where and times when, its quantity is

20 much its influence on the photographic elements 11 is also more than is desired, hindering the R.G.B. filter from forming an ideal color tone and making it impossible to produce clear images.

With a view to preventing this latter from occurring, conventional cameras have an infrared-ray filter set behind the lens 5 cvlinder inside them to have it shut off much infrared ray, but the

problem is that this filter is fixed unmovable, wherefore under such circumstances as light is very little, part of even the little light is shut off by this fixed filter reducing the illuminance to lower than required for the photographic elements 11 to function, thus undesirably affecting the elements 11 to function, thus undesirably affecting the elements 11 and reducing the photographic sensitivity; and when it is wanted to watch for things outdoor in the darkness by means of an infrared lamp or luminous diode LED it is impossible to do so because of the fixed filter.

Summary of The Invention

The present invention is intended to solve such problems as given above. The device for controlling an infrared-ray filter inside cameras of the present invention makes role of shutting off infrared ray in the rear of the lens cylinder inside a camera, by the bye, said device is characterized by consisting of a catching protuberance formed in the center of the operation lever attaching said filter; one side of the joining block, with a catching hole on the other side of it to receive said catching protuberance, is inserted so as to be able to more back and forth internally in an electric magnet which is connected with publicly known sensor of illuminance of light, and said operation lever rotates in association with said joining block.

Therefore the passage of light in the rear of said lens cylinder is shut selectively and then the amount of infrared-ray reached to the photographic elements can be controlled pertinently.

Brief Description of Drawings

Fig. 1 is a side-view of an opening and shutting device of the infrared-ray filter in accordance with the present invention.

Fig. 2 is a perspective view of an opening and shutting device of the infrared-ray filter in accordance with the present invention.

Fig. 3 is a dismantled perspective view of an opening and shutting device of the infrared-ray filter in accordance with the present invention.

Detailed Description of the Invention

The present invention will be described, in detail, with reference to the attached drawings as is given below:

As will be seen in Figs. 1 through 3, the present device for opening and shutting the filter inside a camera is made of a supporting board 1, in whose under part the rear end of a lens cylinder 2 passes through and is fixed, and on whose upper part a hinge peg 3 is formed projecting; an operation lever 5, in whose upper part an insertion hole 3' is formed to receive said hinge peg 3, to whose under part a filter for adjustment of ultrared-ray absorption is attached, and in whose central part a catching protuberance 6 is formed; a joining block 7, whose one side, with a catching hole 6' on the other side of it to receive a catching protuberance 6, is inserted so as to be able to move back and forth internally in an electric magnet 10, which is connected with a publicly known sensor of illuminance of light; a pan spring 8, which is fitted elastically between said operation lever 5 and said joining block 7 in order to give the recovery force to said operation lever 5, in a way that its center hole 9 may be passed through by said hinge peg 3, which has passed through said insertion hole 3' joining block 7; and a catching chin 13, formed of one side of said supporting board 1 to control the extent of operation of said operation lever 5.

The function and effects of the device according to the present invention described above will be described below: When much light passes through said lens cylinder 2, the quantity of the infrared ray contained in it is also much, and accordingly the publicly known illuminance sensor starts

functioning, shutting off the power flowing to an electric magnet 10, whereupon said infrared-ray filter 4 of said operation lever 5 rotates in a direction by the recovery force of said pan spring 8 until it is caught at a catching chin 13 and thereby shuts the passage of light in the rear of said lens cylinder 2, thus hindering infrared ray from passing through to said photographic elements 11; when little light passes through said lens cylinder 2 the quantity of infrared ray is also little, and accordingly said illuminance sensor stops functioning, whereupon making power flow to said electric magnet 10 causing the magnetic field around said electric magnet 10 to change and said joining block 7 to get inserted in inside said electric magnet 10, in association with which, said operation lever 5 rotates in the direction opposite to the direction it takes when light is much, thus opening the rear end of said lens cylinder 2 to lead all light including infrared ray to pass through to reach said photographic elements 11.

Accordingly, it is only possible to secure clear images by selectively adjusting the amount of infrared ray by means of the device for controlling the infrared ray filter according as the quantity of infrared ray passing through said lens cylinder 2 is much or little, and when said filter 4 is fully opened, said photographic elements 11 can cover the area where infrared ray functions, even beyond the realm of visible rays' functioning whereby distinction of images gets possible in the dark, thus such cameras, with the use of infrared lamps or luminous diodes LED, can be made available for watch and inspection in the darkness of night, too.