DE2722378A1 - PROCEDURE FOR STEP-BY-STEP TRANSPORTATION OF A FILM AND SUITABLE FILM TRANSPORT SYSTEM FOR PERFORMING THE PROCESS - Google Patents

Description

provided that has access to this transport profile and the overall transport of the film image accordingly controls. The transport profile is preferably parabolic or it is a different minimum energy profile.

In a film camera, the film transport system preferably consists of a marking photo emitter element and position sensors, which are suitable for sensing the film perforation holes. When the film strip once is positioned by reference to the perforation holes, the marker emitter exposes a small area of the filmstrip so that blackening marks are produced in a fixed spatial relationship with each film frame will. These blackening marks can then be sensed by the film transport system of a projector.

Background of the invention

The invention relates to film transport systems for film cameras and projectors, and in particular to step-by-step transport systems, unlike transport systems with constant speed, and the control of a such intermittent system for repeated accurate registration of the film frames with a picture window opening. The invention is also designed so that the significant energy requirements for fast Start-stop operation can be minimized.

Film transport structures are ultimately judged on their ability to precisely register film images, i.e., their ability to move each new film frame along a filmstrip in exactly the same position

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position like the previous film image. Typically, film is made with a series of perforated holes on one or both sides of the filmstrip are provided so that the film frames are positioned by means of mechanical reference to each perforation will. In this way, the film frame positioning accuracy is determined by the variance and distance between each exposed or projected film frame and the associated perforation. The quality of the projected film image is measured as a summation of camera and projector film position variances, the size of the variance being inversely proportional to the perceived Projected image clarity is.

The main disadvantages of conventional mechanical stepping mechanisms can be summarized as follows: First, the many produce moving mechanical Parts that make up the film transport system, collectively acoustic noises that are unfavorable for sound film recording and therefore considerable acoustical shielding of the transport is usually necessary. Second, the large number of precision parts required is precise positioning to achieve, expensive to manufacture, especially with the more precise professional transport systems. Thirdly, the repeated intervention of the transport gripper and, if necessary, the blocking gripper in the film the perforation wears out and its dimensions are changed, so that the capability is reduced will position the film precisely. Fourth, the registration accuracy of the mechanical decreases Parts of the conventional mechanical system due to mechanical wear and tear with prolonged use.

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In recent years, electronic control systems have been developed that attempt to address many of the problems mechanical wear and noise by eliminating the many precision parts of a conventional mechanical equipment replaced by a minimal amount of electronically controlled moving parts will. Such film indexing mechanisms typically achieve film transport and registration by that the film is driven by a ring gear attached to the shaft of a step-driven motor is attached. In U.S. Patent 3,268,287 a system is shown which utilizes a stepper motor describes which is operated with a timing circuit in pulses to advance film frames and to register. Unfortunately, however, stepper motors do not have the angular position accuracy that is necessary to compete with conventional mechanically controlled film transport systems, and they have also been found to produce acoustic noises. The process for higher angular position accuracy is described in U.S. Patent 3,819 wherein the film drive sprocket is provided with a Servo motor controlled by electronic feedback circuit, the angular position and Receives speed feedback signals from an optical encoder disk and a tachometer, which are attached to the drive motor shaft. A considerably more precise film positioning is achieved than with the stepper motor drive, however, certain undesirable problems arise with such an intermittent one servo-controlled mechanism. In step motion devices with fast stop and start, the

ρ largest part of the input energy as IR heat losses

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destroyed in the motor armature windings. This heat loss is proportional to the square of the total load inertia and inversely proportional to the third power of the transport time. The relatively large, sluggish coffers an optical coding disk and a speedometer, together with the very tight transport time restrictions of the film advance movement (generally less than 12 msec) place high energy demands on the system, often noticeable higher than the conventional mechanical stepping mechanism, the motors at constant speed use. This and the resulting higher motor temperature are extremely unfavorable for film transport, especially for portable battery operated cameras.

The above-mentioned ring gear drive system also does not guarantee absolute film position accuracy due to the inherent coupling error between the motor shaft encoder and the film frame that lies in the picture window. Such coupling errors include inaccuracies in the tooth radius and concentricity, the tooth module and the contour of the ring gear teeth, the motor shaft concentricity and the spacing of successive film perforations. Just the inaccuracy of the film perforation spacing prevents such a ring gear drive from reaching the film frame position accuracies that at professional film transport systems are required, despite the angular position integrity of the drive motor. The perforation wear, which is caused by repeated engagement of the gear rim teeth with high acceleration in caused by the film changes the relation by which each individual film frame is registered, so that with over time the clarity of the projected image will be reduced will.

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Frameless drives suffer from the same coupling and manufacturing inaccuracies with the additional Problem of slippage between the film and the drive roller which goes undetected by angle control mechanisms. The positional accuracy of the servo control system described is further reduced by the inability of the electronic circuit restricted, the ring gear steer in both directions. Changes in the system's environmental conditions, such as temperature and Friction, can allow the film to overshoot the intended target position without any possibility of correction consists.

The invention overcomes these disadvantages of conventional transport systems by providing a film transport system is made available with a film position control that meets the requirement for shaft encoders, tachometers or other inertial sensors eliminated, which the energy efficiency and the thermodynamics of the overall mechanism burden. The problem of the relative inaccuracies of the known indirect methods of motor shaft angle measurement is overcome according to the invention by that a device is provided with which directly the positions of the film frames within the picture window and this felt position information for final position control of the film images is used. The accuracy problems associated with the wear and tear of the film perforations become overcome according to a special embodiment of the invention in that a device is provided with the the perforation hole edges of the film are eliminated as a film position reference.

The problem of poor energy efficiency is more conventional Transport systems are further overcome by

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that a novel circuit is made available which is able to track the transport profile of each film transport control so that an ideal profile of the FiIn: - grazing earth movement is vorgewärilk, inderr. the acceleration and speed of the film run with: the 7eit is optimized, including the energy that goes to J-'osir. Lonierunp; .Each film frame is required to be minimized. Additionally In addition to these advantages, the invention also provides for bidirectional control of the end position of each film frame, so that the inaccuracies caused by film transport overflow are eliminated.

Summary of the Fiction n dung

The invention provides a film transport system that can take successive images of a filmstrip transported and positioned exactly at the opening of the picture window of a camera or a projector will. The transport system consists of a drive device with which the film strip is intermittent is transported within the image window of the camera or projector; the intermittent Transport thus ensures that the film transport system has an alternating transport cycle and a rest cycle Has. During the idle cycle, the film image in registration with the image window opening becomes either exposed or projected, depending on whether the transport system is in a camera or a projector is located, during the transport cycle, the next film frame is to be registered with the picture window opening transported. A film positioning sensing device is provided and arranged so that it feels the position of the film image in the image window by feeling prepositioned markings,

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which are spaced along the length of the filmstrip are, wherein the markings are arranged in a fixed spatial relationship to the film image. These Film frame position sensing device generates a film position control signal indicative of the film position within of the image window. Finally, a device is provided with which the film images within the Image windows are positioned to repeatedly register accurately with the image window opening, the Film frame positioning means is responsive to the control signal generated by the film position sensing means will.

The invention also includes a film transport system that minimizes the energy requirements of the system by that in a controlled manner successive film frames within the image window of the camera or projector be transported. In particular, the system has a transport profile control device with which the movement of the filmstrip accordingly during the transport cycle a preselected profile is controlled, and control circuit means by which the filmstrip drive is operated according to the transport profile control device.

Independently of this, a method is made available according to which successive film frames of a filmstrip are made transported for repeated exact registration with an opening of a camera or a projector will. The method is that the filmstrip is intermittent within the image window the camera or the projector is transported during periodic transport cycles, prepositioned Film marks are detected which are arranged along the filmstrip at a distance from one another, wherein the markings in a fixed spatial relationship to the

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Film images lie better .. The last step is the film images positioned in the opening of the film frame with respect to the detected film marks.

It is therefore an object of the invention to make available a film transport system which is capable of extreme movement of the film to register exactly.

In addition, a film transport system is to be made available by the invention, which with low Noise level works.

Veiter is to use the invention to provide a film transport system can be made available, which has few moving parts compared to conventional systems.

Furthermore, a film transport system is to be made available by the invention, in which the shutter and the Film drive can be operated independently of each other.

The invention is also intended to provide a film transport system be made available in which the control and coordination of the moving parts by electrical Facilities is achieved without compromising energy efficiency through use of shaft encoders or the like. With relatively high inertia is necessary.

A further aim of the invention is to make available a film transport system which has film position accuracy which is independent of mechanical wear or film perforation wear.

Furthermore, a film transport system is to be made available by the invention, which is able to

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to transport and register non-perforated film.

Further objects of the invention will become apparent from the following description and claims.

The invention will be explained in more detail with reference to the drawing; show it:

Figure 1 is a view of a segment of a perforated filmstrip;

Fig. 2 is a perspective view of a film transport system according to the invention with the relative Position of film drive mechanisms, film frame and film position sensor;

3 shows a side view of the transport system according to FIG. 2 with further film transport system components as well as locking disc components;

Fig. 4 shows a front view of the closure disc according to FIG the invention with associated photosensors;

Figure 5 is a perspective view of a preferred one Embodiment of the film position photosensor elements, which are mounted on the picture window of the transport system;

Fig. 6 is a perspective view of the film position photo sensors 5 with an additional transport position photosensor for Generating a feedback signal to control the transport profile of the filmstrip;

7 is a perspective view of a film position marking mechanism; how it is used in a camera according to the invention;

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Figure 8 is a block diagram of the electrical control of the preferred embodiment of the invention;

Fig. 9 is a timing diagram of the electrical control signals the circuit of FIG. 8;

Fig. 10 is an illustration of the shutter disc positions for generating the control signals shown in Fig. 9;

Fig. 11 is a block diagram showing the shutter control circuit according to Fig. 8;

Fig. 12 is a schematic of the interrogation integrator circuit according to Fig. 8;

13 schematically shows the transport control circuit according to Fig. 8;

14- schematically shows the end position detector circuit according to Fig. 8;

15 schematically shows the end position control circuit according to Fig. 8; and

FIG. 16 shows a time diagram of the voltage waveforms associated with the operation of the circuit according to FIG are.

Fig. 1 shows a typical section of an image film 11, in which a single perforation hole 13 is used for each film frame 15. In operation, i.e. during of film exposure or film projection, the Film frames 15 individually positioned at an opening, usually at a standardized rate of 24 frames per Second.

In Fig. 2 is a film transport system with a drive device shown, which generally consists of a ring gear 17 on the shaft 19 of a servo-controlled Motor 21 is attached to a housing wall 23

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on the side of the housing wall opposite the ring gear is attached. The film strip is driven on two sides of the ring gear 17 by the teeth of the ring gear engage in the film perforations 13. The film drive also has a stationary pin 27 on, which is arranged under the ring gear 17, so daii the film strip 11 which enters the transport system by being connected to the first side 26 of the ring gear comes into engagement, passed around the stationary pin and returned to the second side 28 of the ring gear to form a tightly driven film loop 29. Instead of the aforementioned stationary A roller can be used for the pen, and a clay roller can be used in place of the ring gear.

As can be seen from Fig. 2, the film strip is transported by the toothed ring 17 into the transport system, where it is guided into a picture window 31, which consists of two parallel guides 331 3 ^, the front one Guide 33 contains a light opening 35. From the image window, the film strip runs around the stationary pin 27 and is returned to the back 28 of the ring gear 17 to engage. Each film frame 15 along the film strip is successively from the ring gear transported to the light opening, where it is then positioned for exposure or projection, depending on whether the Film is used in a camera or a projector.

In Fig. 3, it is further seen that a contoured strip element 37 in connection with the two FiImstreifenfiihrungen 3 ^Q is used 4-1, cooperate so that the guides and the ßtreifenelement to the filmstrip to introduce and to output, when in the transport system enters or leaves this. As

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can also be seen, ensure these three elements actually appropriate engagement and disengagement of the filmstrip with and from the sprocket 17. A Spring loaded side pressure pin 23 is preferably placed in contact with the film loop 29 to To remove lots and play in the loop so that the Film optimally both forwards and backwards while precisely registering each film frame in the can be driven in the manner described below. In some cases, the stationary pin 27 can be optional be spring loaded for the same purpose so that the side load pin 4-3 can be omitted. In each In the event, the pressure element must be adequately cushioned in order to be able to respond to short-term transient forces to prevent being exerted by the ring gear during quick start-stop film positioning.

The transport system of FIGS. 2 and 3 further includes a film positioning sensing device which is arranged so that it senses the position of the film frames in the image window 31 by sensing prepositioned markings spaced along the length of the filmstrip. In the preferred embodiment shown the film position sensing is achieved in that photo emission and photo detector devices directly on the Image windows are provided, specifically, these devices have a photo emitter 45 on the Parallel guide 34- of the picture window 31 is mounted, and a photo detector 51 opposed to the photo emitter ^ • 5 is mounted on the parallel guide 33. This photo emitter and photodetector elements are positioned to provide an optical path therebetween, the is cut through by the film strip 11, and in such a way that film perforations 13 or other pre-exposed film blackenings (Markings) through this optical path

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happen when the film strip goes through the film transport mechanism is transported. Electromagnetic energy emanating from the photo emitter can then be sent to the photo detector pass through to generate a signal in the photodetector indicative of the film position within the image window indicates. Electrical lines 47, 49, 53, 55, emanating from photo emitter 45 or photo detector 51, establish the connection with the control circuit, which will be explained in more detail later. Details will be given later too a special photo emitter and detector explains the film perforations (or other blackening along the Filmstrip) and generate an appropriate control or deviation signal that is sent by the control circuit can be used to precisely register the individual film frames.

During the film frame transport cycle, i.e. when the next frame along the filmstrip for registration is transported with the opening 35, a shutter 61 is placed between the opening and the main objective 59 of the Camera or projector. According to Fig. 4, the closure consists of a segmented disc 61 which axially mounted on the shaft 63 of a separate shutter drive motor 65 which has separate electrical leads 67, 69 has. Because this shutter is mechanically isolated from the film drive, the Shutter operated independently of the movement of the film drive, so that more for the shutter operation Options are available and there is less noise than what would otherwise be due to the mechanical Connections between the film drive and the shutter drive is caused, as is the case with conventional ones Film transport systems is the case. The closure disk 61 rotates so that its outer segments 71 »73 alternating between the film in the picture window

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and the main lens 59 pass through. The locking position and speed is monitored optically with three reflective transducers 75, 77 and 79, the have in a known manner a light source and a suitable photodetector. A number of slotted Holes 81 are radially at equal intervals on a concentric circle around the center of the closure disc 61 and a reflective transducer is mounted near the slotted holes so that the rotation of the shutter disc generates electrical clock pulses that reflect and alternate Non-reflection of the light can be generated on the inner slotted circumference of the closure disc. This Clock pulse of course has a frequency that is directly proportional to the angular velocity of the shutter, and is used as a control signal for the control circuit of the system, as will be explained. The remaining Reflection transducers 75 and 79, which are associated with the shutter disc, are in the vicinity of the outer periphery of the disc around the leading and trailing edges 83 and 85 of the closure disc segments 71, 73 to be detected. The combined signals from the reflection transducers 75, 77 and 79 become this used to control the speed of the shutter and the start and end of the alternating Display rest and transport intervals or cycles of the transport system. During the rest cycle is the Film stationary, so that the film image registered with the opening 35 can be projected or exposed, and during the transport cycle, the next film frame is transported to register with the opening. Details of these signals (Fig. 9) and their use in the control circuitry of the system are discussed later in In connection with the operation and control of the preferred embodiment.

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In Fig. 5, a preferred construction of the photo emission and photodetector device according to FIGS. 2 and 3 when mounted on the picture window 31 is shown. The photo emitter 4-5 consists of a lamp 87, preferably a solid state high output energy element, and a lens 89 positioned between the lamp and the filmstrip 11 to uniformly collimate and concentrate the electromagnetic energy emanating from the photo lamp. The photodetector 51 (according to FIGS. 2 and 3) consists of two photosensors 91, 93 which are arranged closely adjacent. These photosensors, of course, have electrical connections (not shown) in order to carry a signal generated by them to the control circuit of the system. The pair of photosensors 91, 93 are arranged on the emulsion side of the film which is opposite the lamp 87 and the lens 89. As shown, the pair of photosensors is positioned so that the optical path between the lamp and the photosensors intersects the path of the film perforations, as indicated by arrow 95. The wavelength of the energy emitted by lamp 87 is chosen so that it will not be transmitted by the filmstrip but through the perforations. In cameras, these wavelengths are usually limited to the infrared to avoid unwanted exposure of the film.

In the operation of the photo emission and detector device according to FIG. 5 exposed during the End positioning of electromagnetic energy that passes through the perforation 13a, partially one or both photosensors 91 and 93 · The one in each The signal generated by the photosensor varies depending on the area of the photosensor illumination. As explained later the output voltages of the photo sensors input into a differential amplifier whose Output in size and polarity as a deviation signal

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used for film position correction. If how shown in Fig. 5, the perforation 15 a exactly the two photo sensors 91, 93 is centered, the illumination pattern 97 is uniform between the two individual photosensors divided, and the induced voltages are identical, so that a deviation signal Zero is formed, with adapted elements being assumed. This zero position arrangement of the photosensors thereby provides a film position control signal which can be used to convert the film frame 13a into a To drive position that corresponds to the zero or center position 97 of FIG. Appropriately selected photo sensors allow extremely accurate film position registration, with commercially available planar ones Diffusion silicon photodiodes became a resolution and Repeatability achieved to better than 0.25 microns with fast rise times.

In addition to the final film positioning or registration as indicated by the photo emission and Detector device according to FIG. 5 is effected, the film transport system according to the invention further comprises a Transport profile control device which is adapted to the movement of the filmstrip substantially during to control the entire transport cycle before the final and controlled registration is effected. Such a transport profile control device can Have film position detector device according to FIG. FIG. 6 shows the sensing elements according to FIG. 5 and additional sensing elements upstream with respect to the direction of travel of the film. A series of photo emitters 99 are positioned adjacent lamp 87 to direct electromagnetic energy over the path the Film perforation 13b, which is next in position for registration, passes through, and a second lens

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is between photo emitter lamps 99 and the filmstrip 11 arranged to the electromagnetic energy of to collimate these lamps onto the film perforation path and focus. A second elongated photosensor 103 which is a linear photosensor, for example a Schottky barrier photodiode, is disposed adjacent the pair of photosensors 91, 93, and longitudinally with respect to the filmstrip arranged. Preferably, the length of this elongated photosensor is at least one film perforation width greater than the length of each film advance.

In operation, electromagnetic energy from the photo emitters 99 passes through the running film perforation 13b and hits the linear photodetector 103 to produce an electrical signal proportional to the distance of the exposed Area 105 on photodetector 103 from photodetector end 107 to generate. This provides a directional indicator of the exact position of the film perforation in progress 13b is made available to the film drive control circuit with time. At any point in time Before the current film frame reaches its end position, the film position is monitored by the photo detector switched to the photodetector pair 91,93, whereupon a high-precision final film position signal is obtained. It it should be pointed out that, in contrast to the sensor arrangement according to FIG. 6, the elongated photodetector 103 and the associated photo emitter elements and the lens can be positioned so that they control entire film transport and end position without using a separate pair of photodetectors 91,93 will. Linear photodiodes are very accurate, like photodetectors, but generally require more

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Stabilizing circuit to provide end position feedback accuracy to ensure in case of temperature fluctuations, compared to zero position detectors.

It is contemplated that the invention not only Perforation holes feel, as just described, to precisely register the film images, but also others Film marks, such as pre-exposed and pre-positioned Mark blackenings. Such an alternative provides important advantages. With repeated intervention every film perforation with the ring gear 1? as described above, or with repeated use of film transport grippers and locking claws like those in more conventional ones Film transport mechanisms are encountered, the shape of the film perforation is changed so that the relationship between the edges or centroids of the film perforation and the corresponding film image is changed. If the integrity of the film perforation is deteriorated, The accuracy of the film image registration also deteriorates accordingly, so that only one is decreased Sharpness of the projected film image is possible. This universal problem is practically eliminated by that pre-exposed and pre-positioned blackouts Position of the filmstrip perforations itself will. Fig. 7 shows a device for marking a film strip, which a film transport system used in a movie camera. In Fig. 7 is the filmstrip 11 and a photodetector pair 91a, 93a shown, the one according to FIG. 5 is identical, except that you can see from the other side of the filmstrip. A series of small photo emitters 109, preferably LED chips, are arranged in the space between the adjacent photodetectors of the pair 91a, 93a. A mask 111 is between the series of photo emitters and

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placed on the filmstrip so that the photo emitters chosen to emit a wavelength to which the filmstrip is sensitive, emit through an opening 113 in the mask, the circumference of which is larger is than the film perforation registering with it. the Mask 111 allows electromagnetic energy to flow from the LED pass through to expose the film within the confines of the nose opening so that the effective blackening area extends beyond the edges of the film boundary around the perforation. the Positioning of the film in the camera for exposure and marking is done by the same perforation detection mechanism achieved, as shown in Fig. 5 or 6. Frat after the film drive motor is de-energized and the corresponding film image is registered with the opening 35, the small photo emitters 109 are actuated, to expose the border of the perforation. The D- ^ uer the exposure through the photo emitter 109 becomes less than or equal to the exposure of the corresponding film image chosen because it is necessary that they are de-excited before moving on to the next film frame, when the filmstrip is chemically processed, each film perforation marked in this way shows one clear or colored blackout border 115, the centroid of which is an identical, known distance from each concerned measures exposed film frame for all film frames along the entire film strip. One this way exposed film strip which is brought into a projector with a film transport system according to the invention is, each film frame repeatedly correctly registers, despite perforation wear, because the photo sensors 91 and 93 (according to FIG. 5) detect the blackening edges instead of the perforation edges. With regard to the

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Accuracy of the projected image will contribute to error extremely practical due to the camera film positioning mechanism eliminated; since the film registration position each When exposed in the camera, the film image is permanently on the film strip by means of the detectable circumferential markings 115 is recorded.

Many possibilities in terms of film transport operation and construction are provided by this new film registration channel opened. Because camera film registration errors are practically due to exposure are eliminated by blackening on the edge of the film strip, it is conceivable that a film marking device 7 can easily be adapted to conventional cameras without the need for a precise film positioning device as described here. That would of course also be a necessity eliminate the need to provide film position detectors 91a and 93a in the camera as shown in FIG.

Of course, the concept, a blackening perforation edge provide on transparent lines, circles, squares, rectangles or other geometric Shapes at any fixed point between the perforations along the filmstrip. In this way the projector film transport system would do not detect a transparent perforation edge, but an optical marking or a window between the perforations. It would also be conceivable to have more than one optical marking or blackening per To use film image and to use film strips in which the exposed optical markings are dated Manufacturers are provided.

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operation

Operation of the mechanical part of the preferred embodiment The invention works as follows: The shutter motor 65 is energized to rotate the shutter disc 61 to rotate. The angular velocity of the shutter disk is measured with a reflection transducer 77 monitored, who takes advantage of the slotted holes 81 spaced around the inner circumference of the closure disc are arranged from each other. As soon as the closure disc reaches the desired angular speed, the Combination of signals provided by reflection transducers 75 and 79 gated so that a signal is generated which indicates the beginning of the closed position of the closure disc. This Shutter position signal actuates the film drive in order to transport the next film frame into the opening 35. When the film image is transported, the film sensing device senses consisting of photo emitter 45 and photo detector 51 ani film gate, the perforation on the edge of the film strip that corresponds to the transported film image. Instead, a pre-exposed border around the perforation hole can be detected. The ones from the sensing elements of the picture window generated control signals are input to the control circuit, which is described in more detail below, which in turn controls the operation of the servomotor 21 for driving the ring gear 17 in order to produce the film image, which corresponds to the felt film perforation, precisely to register with the image window opening 35. Of the Engagement of the film strip around the two sides of the ring gear 17 and the tension in the film loop 29 by the spring-loaded side pressure pin 43 allow bidirectional movement and control of the filmstrip for final positioning of the film frame by the servo motor 21.

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The total time available for film transport and registration is usually and is preferably IO msec. A short one Time interval after which the film frame is finally positioned is, the shutter has rotated to the beginning of the open position, i.e. one of the disc segments 71 or 73 begins to clear the film opening 35. At this point, a signal from the shutter control circuit shows enters this condition and de-energizes the film drive motor 21 so that the no-transport or cow cycle begins. During the dormant cycle, the open shutter exposes the film registered with the opening. in the In the case of camera operation, this sleep cycle exposure period can also be used to cover an area 115 µm to expose the corresponding film perforation or to produce other suitable film marks. As soon the shutter disc is rotated at the beginning of the shutter position, signals the shutter control circuit the film drive control circuit that can be fed to the next film frame, and the transport cycle described above is repeated.

Energy considerations and Filmtran s portste and augmentation

A quick start-stop movement requires in everyone Use case considerably more energy than a continuous one Movement to move a specific cash register, it is therefore necessary to use the speed profiles of movement, load inertia, friction, angular displacements and time to be chosen so that the energy requirements can be minimized and the heat dissipation is not harmful to the operation of the film transport system

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will. The heat losses in the armature winding of the FiImantriebsmot, ors are the main energy consumers of the input energy for the drive motor. As armature winding heat losses Energy dissipated per film transport is diverted to

" ^{Γ fc} a

κ ² ^ κ ²
Did

where: E means dissipated energy; r is the electrical resistance of the drive motor armature; K, ~ the torque constant the drive motor; J is the total load inertia driven by the motor; T is the total frictional torque overcome by the motor when driving the load will; 0 the angular step of the motor for each transport; t is the transport time and C is a constant passed through determining the actual speed profile that the engine will follow during transport.

The practical limits of the transport time t are roughly 7 to 12 msec, preferably about 10 msec. Shorter times physically stress the film due to high acceleration during transport and are impractical from an energy standpoint. Longer times represent an unfavorable compromise in terms of the time taken for film exposure normal running speeds of 24 frames per second available i3t. These short transport times ensure that the inertia components of the energy dissipation Friction components by far predominate, the latter are comparatively practically non-existent. The minimization So the load inertia of the system is the main consideration for the design.

The invention minimizes the unfavorable inertia loads in that the moving parts of the film drive on

the film 11, the toothed drum 17 and the servo motor 21 with its shaft 19 are restricted. Shaft encoder and tachometers commonly used in feedback control are eliminated. With the exception of the ring gear 17, all film guides are preferably stationary or non-positive and not rolling or sluggish, since every increase in load inertia is included in the energy consumption as a square.

With regard to the construction of the ring gear, which is a As an important element of inertia in the invention, there are several conflicting dynamic considerations important. Minimizing inertia requires the use of small radii and low budget materials in the construction of the ring gear. However, small radii increase the angle steps (Θ in the energy equation above) for each film advance, and reduce the number of sprocket teeth that hold the film during the high Hold acceleration. Small radii result, in a positive sense, in a higher accuracy of the film registration for a given engine thanks to the smaller tangential Displacements per unit of rotation angle.

It should be mentioned that a toothless drum has many advantages over a toothed drum in terms of Energy efficiency and noise, can be used in place of the toothed drum 17. Because a toothless one The drum is not set up for tooth engagement in the film, its radius can be smaller, so that considerable lower load inertia occurs. It is believed that this is true even though a toothless design Drum may require squeezing rollers subject to inertia, with which the film is held on the drum. Use existing intermittent film transport systems no toothless drums because of the inaccuracies

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the film position, the lack of form fit of the film with the drum. if there is no positive engagement, there is a slip between the drum and the film during the rapid i'tart-stop movement of the intermittent Operation, and such slippage occurs even if the film position is changed by the angular position of the Motor shaft is controlled by shaft encoder or Maltese cross. The invention addresses such slip problems not subject because the film position feedback and control is direct from the film in the image window is removed by sensing pre-positioned markings on the film, so any slip, that can occur can be measured and corrected without losing film registration accuracy.

It should be noted that a toothless drum drive can be used with a pinch roller so that the film is driven from only one side of the drum (as opposed to the two-sided engagement at a toothed drum). A bidirectional control is feasible in this way, since a toothless drum brings practically no dead game between engine and film. Preferably the toothless drum drives the film within the image window to a linear section of film between the drum, position sensor and to ensure opening. In this way, the stationary pin 27, the film guides 37, 39 and 41, the side push pin 43 and the film loop 29 are omitted will.

It is also important that by using a toothless drum instead of a toothed drum and a

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Film positioning marking device according to FIG. 7 in Take into account that film perforations are complete can be omitted.

The second important consideration of inertia in designing the drive of the invention is choice of the drive motor 21. A low inertia of the motor, a low electrical resistance of the armature low static frictional torque and a high torque constant are important. In the case of film cameras, film drive motors are extremely good in performance required in terms of size, weight and energy restrictions.

In addition to minimizing inertia loads as described, the film transport system of the invention provides also for a transport profile control device, which is designed so that the movement of the filmstrip during of the transport is controlled by the servomotor 21. The transport profile can of course be printed out in a Speed profile or a position profile or a combination of the two. In the case of a speed profile, the profile would Describe the speed of the filmstrip from the beginning of the transport to the end of the transport. That ideal speed profile for a stop-start angular rotation is parabolic, with the angular velocity of the motor shaft increasing parabolically over time and falls. This optimal speed profile is characterized by the following equation:

w (t) = -τη (t - t) t

CX

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where w (t) is the angular velocity of the drive motor at any point in time t between 0 and the total Film transport time t is.

For the parabolic profile, the speed profile constant C in the above energy consumption equation has a value of 12. Conventional transport ay stars usually follow a trapezoidal, oiler triangular speed profile with a minimum C value of 13.5 or 16. These C -Values actually increase because you don't follow the profiles perfectly. The invention provides a control circuit, which will be described later, which precisely controls the transport profile of the filmstrip by storing a preprogrammed transport profile and comparing this stored information with an appropriately generated signal indicative of the actual film position or speed. The transport position detector device according to FIG. 6 is an alternative for generating such a signal indicating the position. By using the transport profile control according to the invention, profiles can be achieved which can achieve an energy efficiency previously unknown in technology.

Control circuits

Referring to Figure 8, the preferred overall control circuit becomes for actuating the transport system drive, it is expediently divided into three parts: the first part is a circuit for generating a trigger signal,

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8 0 982 1/0538

which consists essentially of the shutter control 121 and the start, stop signal generator 123 consists. The shutter control is operatively connected to the shutter drive motor 65 and the start-stop signal generator derives its input from photo sensors 75 and 79, associated with the closure disk 61. The second part contains a first control circuit for Activating the drive motor 21 for a time during the transport cycle that is sufficient to remove the filmstrip to be transported in such a way that the next film frame comes approximately in registration with the opening 35. These The first control circuit consists essentially of the transport control circuit 125 based on the circuit however, according to Fig. β, it also operationally includes the end position detector 127, a mono-flop 129, and a Interrogation integrator 131. These circuits 125, 127, 129, 131 cooperate, as will be described below, to create the To control the transport of the film strip by a suitable signal for actuating the drive motor 21 is generated by power amplifier 140. The third Part of the overall control circuit consists of a second control circuit for the final positioning of the film, the in addition to the first control is also able to control the drive motor 21 through power amplifiers 140 to activate. This end position control circuit has the end position control circuit 133 as they are is used in conjunction with the end position detector 127, and is provided with an end position start command signal 135 activated.

The on-off switch 137 shown in FIG. 8 activates and deactivates the shutter control 121. In the following it is assumed that this switch is in the position "A" iet. Activation of switch 137 provides

... / 30 809821/0 5 38

for that, dni! the oscillator 139 has a preselected one Frequency Inuft to generate the control signal A (Fig. 9) is used to determine the speed of the Locking motor 65 and thus the angular velocity the lock washer 61 to control. The oscillator can be controlled with a variable RC view, which is from the outside of the camera or the projector set, can be, and can be provided with a very fine tuning control to the exact number the desired frames per second to choose.

When the shutter disc rotates, the disc seas; elements 71, 73 pass through the photodiodes 75 and 79 » to generate signals B and C (Fig. 9) defining the duration of exposure (or projection), which is above has been referred to as the resting cycle. It will also the voltage curve D (Fig. 9) is generated, which defines the time between two exposures, above as Transport cycle was designated. The peak of the voltage curve E (Fig. 9) indicates the beginning of the Transport cycle on, and the peak of the voltage curve F means the end of the transport cycle. The peak of the voltage curve F also indicates the beginning of the exposure pro jection cycle.

Fig. 10 shows a possible arrangement of the reflection transducers 75 and 79 with respect to the closure disc to generate the voltage curves described above. The left locking position shows the position of the Shutter disc just before exposure / projection, and the right shutter disc position shows the Shutter disc just after exposure / projection. As can be seen in the left part of FIG. 10, the Transducer 79 "switched off" when the trailing edge 85a moves into the illustrated locking position. the

... / 31 809821/0538

positive edge of the voltage curve C is thereby generated as a valid stop signal for the transport control. When the shutter is anti-clockwise rotates into the position shown on the right in FIG. 10, the trailing edge 85a passes over the transducer 75 » so that your converter is "switched off" in order to generate the positive signal of the voltage curve B. the The positive edge of the voltage curve 3 thus means the start of the transport cycle, since the opening 35 is now is covered by the closure disk segment 71.

The voltage curves B and C are combined to form the voltage curve D by inverting C and they are both sent through an AND gate by the leading edge of the voltage curve D a start signal and the trailing edge represents a stop signal!:. It should be mentioned that the voltage curve D, the transport and rest cycles of the Transport systems describes can be used to mark photo emitters 109 during rest or Turn exposure cycle to the reference mark redaction to expose.

The start-f.top signal generator l.?3 supplies a start-stop control signal, as described above in connection with Figure 9D to the transport control circuit to operate. The transport control circuit 125, when activated, in turn supplies a signal which is the preferred one Movement profile for the transport indicates as it is through the theoretical energy considerations described above has been derived. This profile can indicate a position or speed, or a suitable tension or a reference current of the time, and is used to that actually

... / 52 H Cj 9 8 2 1/0 S 3 8

felt film position or speed, or the Compare the reference voltage or the reference current. The control profile is preferably stored in a memory and is visited over time, or with generated by a function generator, but instead it can be a continuously calculated arithmetic Be profile in the control circuit. The former method is preferred because of its smaller feedback loop time constants are involved. As described above, position feedback using the linear elongated photodetector 103 of Fig. 6 can be obtained. The speed feedback can be linear Photodetector or by measuring the back emf of the motor. Voltage and current feedback can can be obtained directly from the terminals of the motor 21.

That used in the circuits of FIGS. 8 and 13 Transport control, which is described below contains a saved speed profile, voltage feedback from drive motor 21, and deviation signal feedback and storage means an interrogation integrator 131. It should be noted that the following description of the circuits of FIG and FIG. 13 merely contains a solution for the transport control, a possible feedback alternative having already been described in some details above in connection with the position feedback obtained by the photodetector 103 of FIG.

In operation, the transport control circuit 125 operates 8 the drive motor 21 to drive the filmstrip to move very close to the end position, which is necessary to accurately to the next film frame

... / 33 ^ö 09821/0538

"si

to register. The transport control circuit internally generates the voltage curve G (FIG. 9), which defines the duration of the initial transport defined by the transport control circuit. At the end of the signal defined by the voltage curve G, the mono-flop 129 generates a deviation inquiry command signal H (FIG. 9) which is input to the inquiry integrator 131. The duration of the mono-flop pulse H determines the integration time of the query integrator. It is important that the deviation interrogation pulse is terminated before the end position circuit 133 is actuated because the interrogation integrator must fully integrate the signal from the end position detector, to generate a deviation signal that is the offset of the filmstrip from the desired exact location represents. As already described, the signal from the end position detector is taken from the pair of photodetectors 91 »93 generated according to FIG. 5, which prepositioned the position of the perforation hole in the film strip or another Along the filmstrip. The deviation signal generated by the query integrator 131, is fed back to the transport control circuit 125 in order to change the transport profile of the next film transport to be used so that the previously encountered deviation is reduced by anticipation.

The duration of the end position control (by the end position control circuit 133) for the final positioning of the film frame during the remainder of the transport cycle is shown by the voltage curve I in FIG. As shown, the signal comes to Actuation of the end position control circuit voar the same pair of photodetectors 91, 93 that send the signal to the interrogation integrator 131 delivers. The duration of the end position control, represented by voltage curve I.

... / 34 809821/0538

can be determined by any suitable gating of the mono-flop signal (voltage curve H) and voltage curves C, D or F. Regarding Voltage curve I should be noted that the resulting gated signal is used for every further positioning Beyond the transport cycle of the transport system prevented .

In Fig. 11, a circuit structure for the shutter controller 121 of Fig. 8 is shown. The in Fig. 11 The circuit shown is a conventional phase-locked loop circuit consisting of a phase comparator 14-1, which is followed by a low-pass filter 143, the again an amplifier 145 follows. The angular velocity information the shutter disc, those of the shutter disc slots 81 and the reflective photoconductor 77 is derived, is fed back to the phase comparator. This circuit is "phase locked", when the frequency of the command signal from the oscillator and the feedback signal from the shutter disc become identical. When the control signal from the oscillator is constant it will therefore provide a constant shutter motor speed. The electrical components of this phase-locked loop circuit must be selected in this way That the system is stable, and some compensation may be necessary to adjust the open loop gain to reduce that can cause instability.

The stop-start signal generator 123 according to FIG. 8 is a simple detector, not shown, with which the signals are detected which are generated by the photodetectors 75 and 79, which are located behind the shutter disc

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are arranged as shown in FIG. A voltage comparator circuit is used to Generate voltage levels compatible with digital circuits and become appropriate gates used to derive the voltage curve D in FIG. The voltage waveform D ensures that the motor actuation circuits are completely de-excited at the beginning of the exposure-projection cycle, and further ensure that the transportation of the transportation system is within the limits dictated by the invention Time parameter is going on.

14 shows a suitable circuit for the end position detector 127. As shown, the two photodetectors 91.93 are connected to two operational amplifiers I5I or 153 that are selected to be used as High performance buffers act before the signals from the photodetectors enter operational amplifier 155. A potentiometer 15? is at one input of the operational amplifier 153 is provided to allow this amplifier to be zeroed. The output of amplifier 155 leads according to FIG. 8 to the input of the end position control circuit 133

The light emitting lamp 87 that the photo detectors 91, 93 is irradiated only during the by the Voltage curves H and I in Fig. 9 defined times switched on. This ensures that minimal energy requirements can be achieved.

One possible embodiment of the interrogation integrator circuit 131 is shown in FIG. The query integrator circuit consists of an electronic

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Switch 161, which is switched on and off with the pulse H from the monoflop 129. The switch 161 is in Series with an integrator circuit 163, which holds the charge at least until the next film transport should take place. As shown, the output of the integrator circuit 163 is with a voltage follower 165 buffered to produce a low impedance output at 167. It should be noted that the integrator circuit can be reset when power is first switched on by temporarily using an externally operated Switch 169 is closed, so that the capacitor 171 discharges through resistor 173. About integration to start generating a deviation signal for the transport control circuit 125, the integrator circuit switch 169 open and switch 161 closed. At the end of the integration period, the Switch 161 opened to prevent further integration of the incoming signal, and after this time integrator circuit 163 holds its voltage on capacitor 171 for final reading at output 167 By repeatedly integrating the error signal input from the end position detector 127, the transport cycle becomes optimized within a few transports of film images. The output from this circuit stays for a considerable amount of time at the integrated level, depending on the quality of the components chosen this circuit, so that stored deviation information is obtained which is capable of the Transport cycle over a continuous operation of the transport system. The resulting deviation signal from the interrogation integrator 131 becomes this used to position the film frame closer to the desired registration during the transport cycle, so

... / 37

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that after several transports the need for further positioning by the final position control circuit 155 is essentially eliminated.

Fig. 13 shows a preferred circuit implementation for the transport control circuit 125 and is divided into three parts: the first part, labeled 181, is a voltage controlled oscillator circuit using a commercially available integrated circuit chip. Matched monolithic transistors 185, 187 are provided to improve the control linearity of the circuit and are connected as a current mirror. The frequency output from this oscillator circuit is proportional to the mirror current (Type 555 is a well known, commercially available timer circuit). In the case of changes in conditions, for example changes in friction, the last transport may be too short, so that the final positioning of the image must be readjusted by the end position detector 127 and the end position control circuit 133 according to FIG. In the event of a deviation after the first transport cycle, the deviation signal generated by the interrogation integrator 13I is input to the matched transistor pair 185,187 through resistor 189, with the result that the oscillator frequency is changed to change the initial transport time accordingly. The result is that the next film transport brings the film frame closer to the desired position. A suitable device may be added to the oscillator frequency to be adjusted initially that the transport it reaches the destination ■ little or no deviation.

The second part of the transport control circuit 125 is a digital function generator 191 * of a

... / 38 809821/0538

8-bit binary counter 193, a read-only memory (EOF!) 195 and a digital-to-analog converter 197. When the start signal from the start-stop signal generator 123 is the counter 193 is set to logic zero. The start signal prepares the counter, which then goes through all of its logic states counts. In the last state, when all outputs of the counter are logical ones, this is done by a Detected gate with eight inputs, which in turn switches off the clock for the counter. That means that the Read only memory address is 255 and the content of this The address is selected so that the read-only memory ensures that the motor comes to a complete stop. The output of the gate 199 supplies a signal for the actuation of the Konoflop 129, which, as described above, enables that a deviation signal for use in the next Film transport is generated.

The digital-to-analog converter 197 is used to generate an input signal for the third part of the transport control circuit, ie the DC motor control circuit 201, and specifically provides a signal for motor voltage control. This signal can be optimized by means of the words of the 8-bit read-only memory so that a control signal is input to the DC motor control circuit 201 which ensures that the engine 21 responds with a nearly perfect parabolic velocity profile. The profile signal is generated as the counter 193 sequentially addresses each address of the read-only memory which stores the profile information until the last address of the read-only memory is reached . Preferably, the first address of the read-only memory is programmed so that it has a higher output than would be dictated by a true parabolic curve in order to ensure that the stopping force for the static friction is achieved. That trait, a breakout force

... / 39 809821/0538

to deliver demonstrates the adaptability of the stored transport profile according to the invention.

The first two parts of the transport control circuit consist of the illustrated embodiment voltage controlled oscillator 181 and the digital function generator 191, it should be noted, however, that these parts of the circuit can also be realized by a suitable analog function generator.

The third part 201 of the transport control circuit according to FIG. 1 consists of a suitable connection between the function generator 191 and the power amplifier 140. A voltage follower 192 serves to buffer the signal from the digital-to-analog converter 197, while the transistor switch 20? is used to selectively operate the motor 21 by providing a control signal to the summation node for the time period defined by the voltage curve G in FIG. As shown, the control signal is input at the summation node to power amplifier 14-0 which in turn drives motor 21 to advance the film. Since the power amplifier can drive the motor in a positive or negative direction depending on the polarity of the control signal applied to summation node 200, amplifier 140 can be used for both main transport and bi-directional end positioning of the film strip by end position control circuit 133. An external resistor 203 in series with the armature of the motor provides positive feedback 207 to the power amplifier 140, which serves to compensate for the internal resistance of the motor armature. With this feedback setup, the applied motor voltage is strictly controlled in accordance with the control signal input from summation node 200 .

... / 40 80382 1/0538

Kit reference to the circuit according to Fig. 13 should be mentioned that occasionally small voltage spikes may appear at the output of gate 199, because of inherent Delays in a ripple counter. These tips must be avoided because they could trigger the monoflop 129. To avoid this problem it is suggested that that a synchronous counter is used, or a suitable filter circuit to filter out the voltage peaks. It should also be mentioned with respect to the transport control circuit that the circuit of FIG can be used to transport the filmstrip backwards as well as forwards without the Registration accuracy is deteriorated. This can be achieved simply by using the electrical Inputs for the drive motor 21 are reversed, or the polarity of the applied voltage signal is reversed will.

FIG. 15 shows the preferred circuit for the end position control circuit 133, and FIG. 16 shows the voltage waveforms associated with the circuit of FIG. The circuit of Fig. 15 consists of a comparator circuit 300 which has as a central element a comparator 302 in the form of an open loop operational amplifier, one input of which is directly electrically connected to the output of the end position detector circuit 127 in order to receive the film position control signal generated thereby , and the second input sees a reference voltage which is indicated in the drawing with S '/ 2. The comparator input reference voltage S '/ 2 is derived from the signal S ¹ , which is held in the interrogation circuit 301, and represents a fraction, preferably exactly half, of the stored signal S'. The query circuit 301 queries the detector output with a pulse from the monoflop 329, the

... / 41 809821/0538

The monoflop is triggered after the initial film transport, ie after the trailing edge of the voltage curve G in FIG. 9, and then, as will be described below, from the output 305 of the comparator timing control circuit 3CW-. It should be mentioned that the monoflop pulse also simultaneously de-energizes the output of the comparator by means of the transistor switch 307, which when the monoflop pulse occurs (or a stop signal described later) the comparator output current (denoted by I-sum), which flows to the gummation node according to FIG , stuck to zero. A de-energization of the comparator circuit output causes the motor to be de-energized so that a fixed deviation in the film position can be established and detected by the end position detector 127, and that the resulting constant film position control signal, which is generated by the end position detector, is interrogated by the simultaneously prepared interrogation circuit and can be saved.

After the end of the first pulse from the monoflop 329 the query circuit holds 301 prepared or "turned on", so that a constant comparator voltage V drive is applied to the motor 21, the sampled signal and the output of the comparator circuit 300 is to the film to its end -Register position to drive. As the film moves to its final position, the film position control signal, which is input directly to the comparator 302, decreases; if this signal is equal to the preferred reference voltage S '/ 2, which, as mentioned, is derived from the originally stored deviation ^{signal S 1} , the filmstrip has probably moved halfway to its target position. At this point in the final transport cycle, the polarity of the output of the comparator 302 is reversed so that the

... A2 80982W0538

Motor is constant assumed by the condition Acceleration changes to a condition of assumed constant braking. After the film strip with the drive motor has been braked for a time assumed or calculated to be him brings it to zero speed, a suitable stop signal or monoflop signal can be used to to excite the comparator circuit output again, do turn to de-energize the drive motor.

Because of inherent inaccuracies in the assumption that the acceleration and deceleration of the drive motor with constant and equal rates takes place, and due to friction changes in the system it is considered that the end position is not reached in the first final transport, and that the acceleration and Delay cycle must be repeated. The repetition of the cycle is achieved by the previous drive motor acceleration-deceleration cycle is de-excited with a pulse from the monoflop 329. During the finite duration of this pulse, the interrogation circuit again interrogates the film position control signal which is now generated by the end position detector. A new comparator reference voltage is generated by such a new interrogation S '/ 2 built up. At the end of the monoflop pulse the whole acceleration-deceleration transport cycle repeats itself, but with reference to the new reference voltage S '/ 2. When an overflow occurs, the polarities of the comparator input signals are simply reversed so that the motor goes in the opposite direction is driven. It can therefore be seen that the end position control circuit delivers a bidirectional drive option, and a repetitive option Zeroing queries and transports to the target position,

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to precisely register the film image. The repetition of the transports can be derived by any suitable Stop signal inputted to transistor switch 307 through OR gate 310. Such a stop signal can be derived, for example, from the voltage curve D in FIG. 9, which indicates that an exposure immediately follows, or that a "zero deviation" signal is generated, indicating that the film is at its target position within certain precision limits. A signal "deviation zero" can are generated in that two comparators, not shown, are used, the two threshold reference voltages so that when the signal input from the end position detector 127 to the comparators is within of these reference voltages, a stop signal is generated. A stop signal can also come through instead a suitable counter circuit can be generated which is set so that η pulses from the monoflop 329 are counted and which can be reset to zero when the monoflop 129 pulsates in FIG. 8 (cf. voltage curve H in FIG. 9).

The one-shot 329, which pulses to de-energize the output of the comparator circuit 300, is controlled by the comparator control circuit 304. The principle of circuit 304 is to measure the time it takes to move motor 21 and filmstrip 11 to the half-way position S '/ 2 assuming constant acceleration. In the S ^{1/2-position,} the Komparatorspannungspolarität is reversed and the motor deceleration begins. If the deceleration is progressing at the same rate as the acceleration, the time it takes to come to a standstill (or zero speed) is equal to the time it takes

... / 44 809821/0538

needed to reach the halfway point. The circuit 304 is used to calculate this time and the monoflop 329 at the calculated downtime to trigger. The monoflop pulse then excites the motor for the duration of its pulse. The engine and the Film strips come during the monoflop pulse to a real standstill, during the standstill condition, the interrogation circuit 301 is triggered by the The same monoflop pulse is excited in order to interrogate a new deviation signal from the end position detector 127.

The hold used to calculate the time in which the motor is decelerated up to an assumed standstill condition consists of an integrating circuit 303, a direction memory circuit 308, and a zero crossing detector 309, the output 305 of which is switched in such a way that it triggers the monoflop 329 . The integrating circuit, which is reset by a monoflop pulse or a stop signal via transistor switch 313, integrates the voltage output from comparator 302. In this way, an integrator circuit output Vj- is generated, which is a back-to-back sawtooth function that is proportional is the assumed drive motor speed function. It is that the integrating circuit 304 is excited to allow that the integration starts at the same time at which the output of the comparator circuit is energized to actuate the drive motor to be mentioned. The beginning of the integration and that of the motor acceleration are therefore synchronized.

The integrator output Vy becomes the zero crossing detector 309 is entered which has a zero crossing of V-j. detected,

... Λ5

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so that the calculated time for decelerating the drive motor 21 to a standstill is marked. To the To allow zero-crossing circuit to detect only the zero crossing of the voltage curve V ^, (see. Fig. 16, Voltage curve A), which is associated with the braking cycle of this drive motor, is the direction memory circuit 308 is provided which determines the polarity of the comparator output at the beginning of the acceleration cycle of the Motor saves. This polarity information is fed to an EXCLUSIVELY OR gate 312. The one from the Zero crossings are detected zero crossings denoted by the arrows Z in the voltage curve A in FIG.

When a zero crossing is detected, i.e. when it is assumed that the drive motor is at a standstill, triggers the zero crossing detector 309 the monoflop 329 to the De-energize the motor and reset any part of the limit control circuitry required to control the Prepare circuit for another acceleration and deceleration cycle. The monoflop goes continued, the end position control of the transport system reset and cycle until an appropriate stop signal is input to OR gate 310, as above described.

It should be noted that in order to ensure that on the very first transport the film frame comes close to the end position detector, regardless of load variations, an additional interrogation circuit can be provided to measure the distance which is 5 or 10 % of the total parabolic velocity profile has passed. If a deviation is detected, it will

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Profile corrected and the correction signal for the following Transports saved. The signal source for such an interrogation circuit can be obtained from the film position detector 127 or a separate detector similar to that used in the end position detector.

The invention thus provides a film transport system available for a movie camera or projector made that for extremely accurate film registration ensures these accuracies despite wear and tear or inaccuracies in the mechanical parts of the system is repeated, and in spite of the wear and tear of the film perforation, if prepositioned marks are detected that are independent of the film perforations. in the in the latter case, the invention practically eliminates accumulating registration errors from film cameras and projector. The invention also provides a transport system with maximum energy efficiency through the use of inertia free film position detector devices, minimal inertia loading and one Film transport profile that is optimized in terms of energy. The invention also provides a film transport system that which works comparatively quietly and can be adapted to conventional camera transports can. Furthermore, a means for marking the film in the film camera is made available so that the prepositioned markings can be detected in the projector instead of perforation holes being detected will.

809821/0538

Claims (1)

PATENT LAWYERS DR. CLAUS REINLÄNDER DIPL.-ING. KLAUS BERNHARDT Orthstraße 12 D-βΟΟΟ Munich 60 Telephone 832024/5 2722378 Telex 5212744 Telegrams Interpatent . Ma »1977 V9 Pl D Roger C. FIELD, Munich Kent D. VINCENT, San Jose, CaI., USA Hans-Jürg W. NADIG, Saratoga, CaI., USA Method for the step-by-step transport of a film and for performing the Process suitable film transport system Claims Method for the step-by-step transport of a film through a picture window of a camera or a projector, in which the film is transported intermittently in periodic transport cycles up to the exact registration of a film frame with the picture window opening, characterized in that in a fixed spatial relationship to the individual film frames at a distance ... / A2 P 0 9 8 2 1 / 0S38 ORIGINAL INSPECTED Marks provided from one another along the film can be detected and the film image in each case with reference is finally positioned on the detected film markings on the image window. 2. The method according to claim 1, characterized in that the markings are perforation holes in the film. 3. The method according to claim 1 or 2, characterized in that that the marks are exposed marks. 4. The method according to claim 1, characterized in that the markings in the camera are the perforation holes of the film are that other marks are exposed in the camera and that the marks in the projector the exposed marks are. 5. Method according to one of claims 1 to 4, characterized characterized in that the transport profile is controlled in each transport cycle so that the energy requirement becomes minimal. 6. The method according to claim 5 »characterized in that the speed profile of the transport is substantially has a parabolic shape. 7 · Film transport system for carrying out the method according to one of claims 1 to 6 with an intermittent Drive for the film, characterized by a Fiimposition sensing device, which senses the marks and generates a film position control signal which the Indicating film position in the image window, and positioning means responsive to the film position control signal, with which each film frame is positioned exactly in the image window. ... / A3 809821/0538 8. Film transport system according to claim 7, characterized in that that the film position sensing device has at least one sensing element which is located on the image window in aer Mounted near the picture window opening. 9 · Film transport system according to claim 7 or 8, characterized characterized in that the positioning device has a control circuit for actuating the drive, responsive to the film position control signal. 10. Film transport system according to claim 9, characterized in that that the positioning device has a trigger signal generator that the control circuit during activated during the transport cycle and during the rest cycle deactivated. 11. Film transport system according to claim 9 and 10, characterized in that the control circuit has a first Has part with which the drive is activated so long that the next film frame approximately with the picture window opening registered, and a second part with which the film is finally positioned by the drive is activated based on the film position control signal, and the trigger signal the two parts one after the other activated. 12. Film transport system according to one of claims 7 to 11, characterized in that a transport profile control is provided that controls the movement of the film during transport according to a preselected profile. 13. Film transport system according to claim 12, characterized in that the transport profile control has a memory for a preprogrammed transport profile and gates which have access to the memory and enter the profile into the positioning device. 809821/0538 14. Film transport system according to claim 13, characterized in that that the memory is a read-only memory. 15 · Film transport system according to claim 12, 13 or 14, characterized indicated that the transport profile control a Comprises film position detector which is fed back to the control circuit and an elongated photodetector has, which is arranged in the longitudinal direction of the film such that the next marking runs over it during transport, and which has a variable output signal depending on the location of the point, at which it is irradiated, supplies, and a lighting device that covers the photodetector over its entire length lit by the film. 16. Film transport system according to claim 15, characterized in that the lighting device consists of several Light sources are evenly spaced along the photodetector. 17. Film transport system according to one of claims 8 to 16, characterized in that a light source and a photodetector device are mounted in the vicinity of the picture window opening is mounted on the other 'side of the film path on the picture window. 18. Film transport system according to claim 17, characterized in that the light source and the detector device are mounted so that a film mark is detected when a film frame approximates the Image window opening registered, and the detector signal is used for the final positioning of the film frame. 19 · Film transport system according to claim 17 or 18, characterized characterized in that the photodetector means from ... / A5 80982 1/0538 at least two detectors in a zero position arrangement. 20. Film transport system according to claim 17, 18 or 19, characterized in that the light source emits light, for which only the perforation holes are permeable. 21. Film transport system according to one of claims 17 to 20, characterized in that the light source is a collimator so that the film mark on the photodetector means is projected. 22. Film transport system according to claim 13 and one of the Claims 17 to 21, characterized in that the detector signal is fed to the memory and stored there is used to adjust the speed profile according to the deviation in one transport cycle in the next Correct transport cycle. 23. Film transport system according to one of claims 11 to 22, characterized in that the second part of the control circuit has a comparator which, depending on the Input signals a positive or negative, essentially constant output to the drive Acceleration or deceleration of the film supplies, at one input of which is an interrogation circuit which The excitation interrogates the film position control signal and then holds it until it is reset, the comparator receives a predetermined fraction of the held signal, and the current film position control signal at the other input so that the polarity of the comparator output changes when the current film position control signal falls below the held value, ... / A6 809821/0538 and a device is provided which switches off the output of the comparator for a certain time and energizes the interrogation circuit when it is to be assumed that the film has reached Hull speed, and the
The output of the comparator switches off during the idle cycle and the part of the transport cycle controlled by the first part. 2 ^. Film transport system according to claim 23, characterized in that the fraction of the held signal
half is. 25- film transport system according to one of claims 7 to 2Λ for a film camera, characterized by a marking device for exposing markings on the film in the vicinity of the picture window. 26. Film transport system according to claim 25, characterized in that the marking device consists of a
Light source and a control device for this
that activates the light source when a film image is registered with the image window opening. 27- film transport system according to claim 26, characterized in, that the control device is controlled by the Fiimposition sensor device, which in turn feels the film perforation. 28. Film transport system according to claim 25, 26 or 27, characterized by a mask between the film and the
Light source. 29. Film transport system according to claim 28, characterized in that the mask has a defined field around a
Releases perforation hole for exposure. 809821/0538