SU14254A1 - Cinema projector with optical alignment - Google Patents

Description

The present invention is a film projector in which continuous movement is reported to film I, and two annular prisms with a variable angle of refraction are used as an optical leveling device. The projector carries out continuous motion of the film, ensuring, due to the absence of jerky movements in the mechanism of the Maltese cross, increasing the shelf life of the film. The presence of light interruptions on the screen when moving from one frame to another (one image appears to be in another) eliminates the need to use a shutter, thus saving light.

In FIG. 1 shows a diagram of the film projector of FIG. 2 - ring prism; FIG. 2 and 2 — p1-prism of the prism with two mutually perpendicular diameters; FIG. 3-scan ring prism; FIG. 4, 5, b and 7-scheme of the rays in the projector.

The device of the film projector consists of the following: Between the lens- (Fig. 1) and the screen h there is an annular prism K, the axis of rotation O (Fig. 2) which is parallel to the optical axis of the objective lens M and is in one with it;

horizontal plane. The prism K (Figures 2, 2 and 2) is a glass circular ring, the outer edge of which (a width slightly larger than the objective diameter M) is processed by. over half of a circle in such a way that in expanded form it represents a prism with uniformly decreasing, reaching zero, and again, the angle of refraction increasing uniformly to its original value. The second half of the circumference of the ring is processed in the same way as the first one, so the scan of the entire ring (Fig. 3) represents, say, a two-wave prism (the two-wave form is taken solely for the purpose of balancing the system).

To illuminate a film in a frame: the window uses a second circular prism C with a variable angle of refraction similar to the above described prism f (. The prism C is installed on the same shaft with the prism K and. (Fig. 1). The light beam from the lamp A passes through the diaphragm D, the dimensions of which are proportional to the area of one frame, and enters the lens D. The lens B projects the opening of the diaphragm D in the form of a light quadrilateral equal to one frame. on film L.

When the prism C rotates due to changes in the angle of refraction, the light beam moves with the frame to its lower position in the window, then jumps to the next frame, follows it, and so on. Thus, passing the frame in front of the window E, it is the only one projected by the lens M onto the screen //, where, as stated below, its

The image is held still with a prism / C. Since, when illuminating frames in the upper and lower positions in window E, the light beam will be directed at an angle up or down from the optical axis of the system at a certain angle, a projection lens M with a very large orifice is required to catch all the rays passing through the frame. -eat . In order to be able to use non-existing lens systems (with an active hole

FROM 35 to 52 mm) directly at the window E, an additional capacitor F is placed, which directs all the rays into the lens M with a small active aperture. If one revolution of prisms C and L corresponds to the advancement of the film by two

then, with opposite directions of their motions, the following pattern of the rays is obtained (Figs. 4, 5, 6, and 7).

The illuminated frame is located in the upper part of window B (Fig. 4) and the prism / C is located with a comb along the optical axis of the lens M. If there was no frame, the frame would be projected on the screen / f below the system axis, while the prism K deflects a beam of rays designing an image symmetrical to the optical axis.

FIG. 5 frames advanced by quarter

is of its magnitude, and the prism is one eighth of a turn. A normal projection (without a prism) would give an image displaced with respect to the axis by a quarter of its height, due to the action of the prism (the angle of refraction of which in this area is smaller), the image will again be symmetrical to the axis. FIG. b the illuminated frame is advanced to the middle of the window and the prism is located with its zero point along the axis of the lens. In this case, the projection is symmetric (without and if there is one), since the prism in this case plays only the role of a diverging lens. FIG. 7, the frame is in the lower position in the window and the prism is positioned again with a ridge along the axis of the lens. The path of the rays is similar to FIG; 4 only with a deviation in the opposite direction. Thus, a still image of a frame moving in a window is obtained on the screen. Upon further movement of the film and prism, the next frame is designed, and the entire described cycle repeats again.

By replacing the prisms K and C and the lens M with another, any value of the image on the screen as well as the screen distance can be obtained.

The subject of the patent.

1. Optical alignment film projector, characterized by the use of two annular prisms / C and C with a variable angle of refraction, the first of which is between the lens M and the screen //, and the second C between the frame window and the lens B projecting the light beam from the lamp A through aperture D, corresponding to the area of one frame.

2. When a film projector, indicated in 6 p. 1, applies an additional capacitor F, installed at Frame Window E, in order to direct the light rays into an M lens with a small active aperture. FIG.