Optics: motion pictures – Camera and/or projector drive mechanisms – With indicating means
Patent
1988-07-14
1990-05-01
Hayes, Monroe H.
Optics: motion pictures
Camera and/or projector drive mechanisms
With indicating means
352 4, 352131, 354222, 35428912, G03B 160
Patent
active
049213423
DESCRIPTION:
BRIEF SUMMARY
The present invention concerns a device that may be applied on a 35 mm and other kinds of motion-picture cameras, for effecting cinema shots in low visibility conditions, with a slide being lighted, in its shot field, by a plurality of lighting logics that will determine the protection of the film against electrical and/or mechanical malfunction.
It is well known, devices have been realized with the purpose of limiting the field edge of cinema shots, in conditions of low visibility, which make use of optic fibres and others use slides, placed on the optical run, not in correspondence with the focal plane, so as to determine a considerable inaccuracy in the edge references beyond a frequent possibility of ruining the film, hit by the light emitted for lighting the slide, when there is a lack of synchronism between the lighting and the rotation of the shutter.
It is the aim of the present invention to solve all above mentioned inconveniences of the devices according to the art, in an easy and safe way.
According to the present invention, the aim set forth is reached by means of a device for cinema shots in low visibility conditions, comprising a slide placed on the focal plane, consisting of two coupled elements, a frosted lens and an element provided with references, obtained with the photoengraving process, for the determination of the field edge due to the lighting of said references by a series of leds, lighted by a control from the motor in synchronism with the rotation of the shutter.
The object of the present invention comprises furthermore a sensor for the control of the rotation of the specular shutter and a plurality of electronical logics: one compares the signal of the motor with the one of said sensors and extinguishes the slide lighting leds, lighting a warning light in that case in which the two signals are not in synchronism, and another one that provides the extinguishing of the leds should any malfunction, mechanical or electrical, cause a leds lighting period longer that determined.
The evident advantages of the device according to the present invention are:
the photoengraved reference on the slide lighted by the leds, that allows a good definition of the cinema shot field also in low light conditions.
The logic operated by the sensor prevents in any case the light from the slide from hitting and ruining the film.
The present invention will be described more in detail hereinbelow according to the enclosed drawings showing a preferred embodiment.
FIG. 1 shows a front scheme and an exploded view of the housing of the multiple slide in a camera.
FIG. 2 shows a lateral scheme of the optical run of the light beams.
FIG. 3 shows an axonometric, transparent view of the multiple slide with the placing of the lighting leds.
FIG. 4 shows an axonometric, exploded view of the components of the multiple slide.
FIG. 5 shows a block scheme of the electrical control logics.
The present invention concerns a device for cinema shots in low visibility conditions, that may be applied on 35 mm or other kinds of cameras, comprising a multiple slide 1, consisting of a lens 2 with a frosted surface and of a slide 3, showing references 4 performed by photoengraving and lighted by leds 5 housed in container 6 placed in correspondence with the edge of said slide 3.
Said slide 1 is placed on the focal plane, so that the beams R of the outside image--once the rotation of specular shutter O during working of the camera, causes the same to cover opening A--are no longer able to hit the film P, but will be reflected on said shutter O and reach ocular M thus allowing the operator to determine the field edge.
According to the present invention, said leds 5 are lighted in that moment when the film is covered by shutter O and therefore the vision is in ocular M. Furthermore, the field of the slide 1 corresponds, without any error, to the impression field of film P.
Relating now to the details of the block system of FIG. 5, the following elements are shown: shutter O;
The synchronism for the lighting of the leds 5 is taken fro
REFERENCES:
patent: 2393316 (1946-01-01), Edgerton
patent: 2920134 (1960-01-01), Dresser
patent: 3264930 (1966-08-01), Koeppe
patent: 4101916 (1978-07-01), Gottschalk et al.
patent: 4279481 (1981-07-01), Ishibashi et al.
patent: 4294529 (1981-10-01), Sato et al.
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