SU699477A1 - Device for monitoring the operation of jump mechanism in motion-picture camera - Google Patents

Description

The invention relates to film equipment, namely, devices for controlling the operation of hopping mechanisms and shutters in cinema cameras. A device is known for controlling the operation of the hopping mechanism, which includes an illuminator and a microscope, which directly measures the stability of the position of the perforations of a film charged in a movie camera jlj. Iavestko is also a device for monitoring the stability of rotation of the obturator, in which the direct current light source sends a parallel beam of rays directly to the personnel window of a working imaging device, in the center of which a pulse sensor is installed - a photodetector whose pulse duration determines the exposure time 2. After amplification the impulse goes to the electronic measuring device. A disadvantage of this device is the lack of the possibility of parallel control of the accuracy of the hopping mechanism. The closest in technical essence to the present invention is a device comprising a light source, an objective lens and a photodetector recording a modulated light flux L3J. This device uses an opaque test film, which has a slit in each frame. The light passing through the chips is reflected from the mirror element having the dimensions and shape of a slit and located on the pressure frame of the film channel. The reflected light passes again through the lens and is recorded by a photodetector. The disadvantages of this device are the need to manufacture and use a special test film; the need to install on the clamping frame of a special mirror element or mask With a slit in the frame window; lack of the possibility of parallel control of the accuracy of the hopping mechanism

and the obturator of the transport conditions for monitoring the operation of the jumper Mexaim; svta motion picture camera, since instead of the commonly used film, a test film was used; The measurement accuracy is not high enough because the amplitude modulation of the light flux is proportional to the change in the area of the illuminated part of the mirror element, which is a small part of the reflecting surface.

The purpose of the invention is to expand the functionality and improve the accuracy of control.

For this, two additional photocells are introduced into the proposed device, located respectively on the vertical and horizontal borders of the image plane of the perforation hole.

The drawing shows a schematic diagram of the proposed device;

The device consists of consecutive incandescent lamp 1, sensor sensor 2, prism 3, diaphragm 4 and lens 5. In the film channel 6 formed by the front 7 and rear 8 slide, there is a film 9. Before the perforation hole a is located front skids 7. Photocell 11, 12th 13 incandescent lamp 1 using condenser 2, prism 3 and aperture 4 located in the focal plane of the lens are located in the plane of U along the borders and in the center of the perforation image. 5, through the technological opening b of the front slide 7 of the film channel 6 illuminates with a parallel beam of rays the aperture a of the film 9 and the mirror surface of the rear slide 8 The reflected part of the light beam in the reverse direction through the lens 5 gives an enlarged image 10 in the plane 10 (with photocells on it) films 9 with a perforation hole a and a portion of the mirror surface of the rear sled 8.

Two photocells 11 and 12 are located respectively on the horizontal and vertical borders of the image of the perforation hole a, and the third photocell 13 is located in its center. The magnification L of the image of the perforation is determined by the size

sensitive area of photovoltaic cells and the maximum value of image instability.

Since during the operation of the camera

The boundaries of the perforations of the film are determined by the accuracy of moving it to the frame step, and the reflection coefficient of the film emulsion is several times smaller than the reflection coefficient.

the mirror surface of the rear slide 8 of the film channel 6, the reflected light flux incident on the photocells

11 and 12, varies in the process of transporting the film from frame to frame, i.e., the amplitude of the light flux is modulated. By measuring the difference in the amplitudes of the output signal, the accuracy of the jitter machining is determined, or the magnitude of the image instability,

0 In this case, the photocell 11 measures the vertical instability, and the photocell

12 is horizontal. By changing the period of the output signal from the photocell

13t is the uniformity of rotation of the obturator (not shown in the drawing),

1: information about the accuracy of the hopping mechanism and the obturator is carried out electronically, i.e., the output signal from the photocells is fed through an amplifier (not shown) to an electronic measuring instrument (not shown). measurement accuracy when controlling the operation of the jump mechanism; the errors of film production are eliminated by the fact that the section of the film used in the control moves twice with the jump mechanism for the same perforations, and comparing the data for the first m and second measurements gives the error of the true value of the intermittent operation of the mechanism.

In cinema cameras that are not subject to high image stability requirements, information about the accuracy of the hopping mode is realized visually by a visual method when observing the image plane of the perforation hole in the eye of the microscope (not shown in the chart).

Claims (1)

Invention Formula A device for controlling the operation of the hopping mechanism in a movie camera, comprising a light source, a lens, a photocell and located in the plane of FIG. 56994 channel reflector, which is so that, in order to expand the functionality and increase the accuracy of control, two additional photoelement, pac-s, placed on the vertical, are introduced into it. horizontal and horizontal boundaries of the plane of the image of the perforation hole. 776 Sources of information taken into account in the examination 1. Technique of cinema and television, 1975, N «1, p. 72-73. 2, Technique of film and television, 1973, No. 4 p. 25-28. 3. Austria patent number 241986, cl. 57s132, publ. 1965 (prototype):