Optics: motion pictures – Camera and/or projector drive mechanisms
Reexamination Certificate
1999-06-09
2001-11-20
Adams, Russell (Department: 2851)
Optics: motion pictures
Camera and/or projector drive mechanisms
C352S184000, C352S187000
Reexamination Certificate
active
06318861
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a film positioning system and a method thereof, and more particularly, is suitably applied to a telecine device which converts images recorded on a cinefilm into a video signal, for example.
2. Description of the Related Art
In a telecine device, one frame of images recorded on a cinefilm is positioned on the optical axis of a video camera, and a source light is entered into the pickup system of the video camera through the cinefilm in this state. Thereby, the above positioned frame image is picked up by the video camera.
Moreover, after completing the pickup of the one frame image in this manner, the telecine device feeds the cinefilm and positions the next frame on the optical axis, and performs a similar pickup in this state, so that the images sequentially recorded on the cinefilm are converted into video signals (hereinafter, it is referred to as telecine processing).
In such a telecine device, an intermittent film feeder is provided to intermittently feed a cinefilm frame by frame. In the intermittent film feeders, there are two kinds of intermittent feeding systems, by mechanical control in that the gear teeth of sprockets are engaged with perforations provided on the both ends of the cinefilm in its width direction (sprocket holes on the film) and the above sprockets are intermittently rotated through, e.g., Geneva gears, so that a cinefilm is intermittently fed, and by electronic control in that a motor itself for rotating sprockets is intermittently and rotationally driven, so that a cinefilm is intermittently fed.
In the intermittent feeding system by mechanical control, when the machine is finely regulated, positioning accuracy of a cinefilm becomes fine by being used with a registration pin, so that image pause performance is improved.
By the way, with respect to a feed length per frame in cinefilms, for instance, a feed length corresponding to four perforations is a standard format in a 35 mm film. Other than that, there is a format for high quality mode in which a feed length per frame corresponds to eight perforations, a format for reducing the running cost of a film in which a feed length corresponds to three perforations per frame, etc. Furthermore, recently, various film formats such as a film format of two half perforations per frame, and a film format considering a combinability with a 16 mm film, exist. Therefore, an intermittent film feeder which can easily adapt to these formats and is economical is desired.
However, in the above intermittent film feeder in the intermittent feed system by mechanical control, since its intermittent feed operation is mechanical, it is difficult to adapt to various film formats. Moreover, in some cinefilms, perforation pitch changes as the film itself changes over the years. Since the intermittent film feeder by mechanical control basically adapts to only perforations at a prescribed pitch, if a cinefilm with changed perforation pitch is intermittently fed, there is a possibility of damaging the film itself.
On the other hand, in an intermittent film feeder
200
by the intermittent feeding system by electronical control, as shown in
FIG. 1
, one intermittent feed sprocket
202
is provided to intermittently feed a cinefilm
201
which is supplied from a supply reel (not shown in
FIG. 1
) on a supply side to a winding reel (not shown) on a winding side.
Furthermore, the intermittent film feeder
200
guides the above cinefilm
201
while regulating a feed position of the cinefilm
201
by a film gate
203
at a position on the axis of a video camera (not shown).
The intermittent film feeder
200
has one continuous feed sprocket (not shown) on the supply side and the winding side of the cinefilm
201
respectively. In the state where a flection
210
is generated between the continuous feed sprocket on the supply side and the film gate
203
, and between the continuous feed sprocket on the winding side and the intermittent feed sprocket
202
, respectively, the cinefilm
201
is intermittently fed by being pressed to the film gate
203
under a prescribed pressure with a skate press
204
while rotationally driving the intermittent feed sprocket
202
.
This intermittent feed sprocket
202
is rotationally driven by a DC servomotor (not shown), and the above cinefilm
201
is intermittently fed in the state where the gear teeth are engaged with perforations provided at the both ends of the cinefilm
201
in the width direction. A certain gap is provided in the forward direction of the above perforations so that the gear teeth of the intermittent feed sprocket
202
are smoothly engaged with and disengaged from the perforations of the cinefilm
201
at this time.
Furthermore, the intermittent feed sprocket
202
starts and stops so as to position the cinefilm
201
for each frame by electronical control such as a drive motor or a cam. That is, the intermittent feed sprocket
202
is rotationally driven so as to position the gear teeth pulling the cinefilm
201
to a fixed angle, and the rigidity of the gear teeth is set sufficiently large comparing the film load of the cinefilm
201
.
The skate press
204
is a pressing mechanism to generate a friction F
p
for positioning the frames of the cinefilm
201
stably. For instance, a pressure of 15N degrees is applied to the 35 mm cinefilm
201
, so that a friction F
p
of 4.5N degrees is generated in a direction reverse to the forward feeding direction CW. If the friction F
p
by this skate press
204
is not generated, the feed operation itself for the cinefilm
201
by the intermittent feed sprocket
202
can be performed, however, when the intermittent feed sprocket
202
is stopped, a stable positioning operation cannot be executed because overrun occurs in which a film does not stop at a stop position, owing to the inertia force of the cinefilm
201
.
Moreover, in recent years, the intermittent feeding operation for the cinefilm
201
can be performed at a high speed of 48 frame/sec or more. In such a case, a larger friction F
p
by the skate press
204
is required on the execution of stable positioning of the cinefilm
201
.
In such a telecine device, when the cinefilm
201
is intermittently fed frame by frame by the intermittent film feeder
200
, the friction F
p
by the skate press
204
is applied to the both ends (edge parts) of the cinefilm
201
. Recently, however, since control data such as a digital audio signal and a time code is recorded in these parts, there has been a problem that the friction F
p
by the skate press
204
damages the digital audio signal and the control data or the like.
Furthermore, in a telecine device, when the cinefilm
201
is intermittently fed frame by frame by the intermittent film feeder
200
, if the friction F
p
to be applied was not adjusted according to the differences of the above cinefilm
201
in its kind or being new or old or the like, it is difficult to execute a stable positioning. Even if that can be adjusted, there has been a problem that stable positioning operation cannot be performed since a friction F
p
to be applied to the film changes as the film condition changes with the cinefilm
201
run.
SUMMARY OF THE INVENTION
In view of the foregoing, an object of this invention is to provide a film positioning system and a method thereof that can stably execute a film positioning with a simple configuration.
The foregoing object and other objects of the invention have been achieved by the provision of a film positioning system and a method thereof. In the case where a film is fed in its longitudinal direction and then stopped at a predetermined position, the above film is pulled in a film feeding direction by a prescribed distance by the first feeding means engaged with the film on a supplied side, and the film is sent out in the feeding direction by the prescribed distance by the second feeding means engaged with the film on a supplying side against the film feeding direction synchronizing with the first feeding means, so that th
Adams Russell
Crosby, Heafey Roach & May
Fuller Rodney
Sony Corporation
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