JPS5817969B2 - Kougakushingoki Rokusaiseihoushiki - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a method for recording a control signal in a superimposed manner on the optical sound track of a motion picture film, and using a unique line image of light to discriminately reproduce audio signals and control signals. To control the dynamic system and start and stop the movie film,
Control signals are recorded on the film, but for films that do not have room to record control signals, such as 8mm film and 6mm film sound tracks, the screen is recorded using a section of the screen, or the audio signal is recorded. I have no choice but to record it on the original soundtrack.

Although the method of recording control signals by splitting the screen impairs the projection effect and is not generally adopted, there is a method of recording control signals on the optical sound track of the film. A method in which a signal at a constant frequency is recorded for a short period of time, and a control signal is electrically extracted using a filter during playback. Conductive foil or magnetic conductive material is pasted or coated on the optical sound track, and this is detected using a contact detector or a non-contact detector. A method of detecting with a type detector is known.

These methods have advantages and disadvantages, and are used depending on the purpose of use, but the former method generally has the disadvantage that the filter circuit after the detector is complicated, and the latter method requires less mass production of the same film. There was a drawback that it was difficult to remove.

SUMMARY OF THE INVENTION An object of the present invention is to record a control signal using a set of optical recording power that does not have such drawbacks, that is, is suitable for mass production of the same film, and to enable the recorded control signal to be discriminated and reproduced at a detection end. An object of the present invention is to provide an optical signal recording and reproducing method.

The present invention will be explained below with reference to the drawings.

Figure 1 shows a typical 16mm optical recording film.

In this figure), 1 is the film body, 2 is the screen part, 3
4 is a perforation, and 4 is a general single sound track.

Some of these sound tracks include a double system as shown in Figure 2.

In this figure, 4' and 4'' are similar sound tracks that change in phase, and 5 is a line image of light for reproduction.

As a sound track recording method, a variable area optical recording method in which the amount of transmitted light changes with time, as shown in FIGS. 1 and 2, is generally used.

Traditionally, this method has required that the line image of the light for reproduction must be exactly perpendicular to the sound track.

This principle is the same whether the soundtrack is single or double.

The reason for this is that the waveforms recorded on the track are similar across the center line and change in phase, so if the line image of the light is diagonal to the sound track, the width of the line image of the light can be effectively increased. This is because the high frequency characteristics of the recording signal deteriorate.

In the present invention, the audio signal is recorded by a variable area optical recording method, and when recording the control signal, the sound track on which the audio signal is recorded is recorded with an i constant frequency signal lower than the recording frequency of the audio signal. Partially modulated recording.

The audio signal is reproduced using a line image of light arranged perpendicular to the direction of travel of the sound track,
The control signal reproduces a low frequency control signal component using a line image of light arranged diagonally with respect to the sound track.

FIG. 3 shows a portion of the sound track in which control signals are recorded by the optical recording method of the present invention.

Reference numeral 6 indicates a sound track, and reference numeral 7 indicates a line image of light for reproducing a control signal, which is arranged obliquely to the direction in which the sound track 6 travels.

Although not shown in this figure, a line image of light for reproducing an audio signal is arranged perpendicular to the direction in which the sound track 6 travels.

The waveform of the sound track where only the audio signal is recorded is sound track 4 as shown in Figures 1 and 2.
．． 4' and 4" are similar across the center line, but the part where the control signal is recorded is the sound
The entire track 6 is modulated with a constant frequency signal below the audio signal frequency.

First, when reproducing the control signal, since the light line image 7 is tilted with respect to the sound track 6, a change in the control signal at a low frequency is detected.

Next, in the case of audio signal playback, the pedestal indicated by P is the time.

Even if the optical signal for audio signal reproduction meander within the length range with displacement, the level will not change, so even if the control signal is recorded in a superimposed manner, the pedestal level will be the same as the state before the control signal was superimposed. As long as the setting is such that there is no change in the amount of transmitted light between the portion where the control signal is recorded and the portion where it is not, it is not affected by the control signal (only the audio signal is reproduced).

As described above, according to the present invention, (1) At the detection end portion, the control signal recorded in a superimposed manner with the audio signal can be easily reproduced, and only the audio signal can be reproduced without being affected by the control signal.

(2) The circuit configuration can be simplified compared to the conventional method of using a filter circuit to discriminate a control signal of a specific frequency recorded superimposed on the same sound track along with an audio signal.

(3) Since it uses an optical recording method, mass production of the same film is possible.

・It has the following effects.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing a part of a general 16mm optical recording film, Fig. 2 is an enlarged view of a double-method sound track part, and Fig. 3 is a diagram of a sound track part recorded by the method according to the present invention. It is an enlarged view. 1...Film body, 4, 4', 4"...
...Sound track, 5... Line image of light, 6
7... Line image of light for reproducing control signals.

Claims (1)

[Claims] 1 Record the audio signal using the variable area optical recording method,
A sound track recorded by the above-mentioned recording method is partially modulated and recorded with a frequency signal lower than the recording frequency of the above-mentioned audio signal, and a line image of light arranged perpendicularly to the above-mentioned sound track is recorded. The audio signal is played back using the sound track, and
An optical signal recording and reproducing method in which the control signal is reproduced using a line image of light arranged in the direction of the object.