JPS6139652B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for intermittently feeding films, particularly films having perforation. Recently, a number of 8mm camera cameras with simultaneous recording have been announced.This simultaneous recording method uses a recording microphone to collect signal sounds using a magnetic material approximately 0.7mm wide and 10μ thick on the opposite side of the film emulsion surface. It uses a magnetic recording method that records tracks onto film. In this case, the vibrating parts of the 8mm camera, that is, the movable parts, become a source of noise. For example, the film feed mechanism, zoom lens drive section, film winding mechanism, recording section, and film counter drive mechanism that are normally linked to the shutter are sources of noise. The biggest source of noise among these is the film feed mechanism, and if the recording microphone is not set at a distance of usually 1 meter or more from the main unit, noise will be recorded and the S/N of the signal sound will deteriorate. If the recording microphone is placed close to the main unit, the noise will be so intense that the built-in microphone will no longer be viable as a product.

In this way, the problem with the noise of the influencing machine is the intermittent feeding mechanism of the film, and in 8mm camera, the perflation on one side edge of the film is used to rapidly transport a long film one frame at a time. An intermittent transport mechanism is used. The shutter blocks the optical path while the film is moving, and the exposure time is the time when the film stops and the shutter is out of the optical path. Currently, the standard frame advance speed for 8mm cameras is 18
frames per second, and when shooting in relatively dark conditions such as at night, the shutter opening angle needs to be 240 degrees, so with the intermittent film advance method, the film can be advanced one frame within 1/54 seconds. The camera will then stop and expose for approximately 1/27 second. If the shutter opening angle is extremely large, the blur caused by the flow of the image will become large when photographing a moving object, resulting in drawbacks such as camera shake.

Regarding ``screen oscillation,'' the JIS standard limits the permissible value to within 0.03 mm in both the vertical and horizontal directions when the shooting speed is 24 frames per second or less. The horizontal direction can be solved with a film gate, but the vertical direction is a problem.

Therefore, for an 8mm camera with simultaneous recording, 1/
Move the film approximately 4.2mm for one frame within 54 seconds,
The variation in the film stop position is within 0.03mm,
What is required is something that can intermittent feed at least 18 frames per second and generates little noise.

In addition, with regular 8mm cameras, the film feed speed is increased to 24 frames/second or 36 frames/second for high-speed photography.
It is now possible to change the film advance speed over a wide range of seconds, such as 12, 18, 24, 36, and 72 frames per second on high-performance cameras.

SUMMARY OF THE INVENTION An object of the present invention is to provide a film feeding method which is particularly suitable for the above-mentioned 8mm camera, which produces less operational noise, and which allows the feeding speed to be easily changed.

In the film feeding method of the present invention, a signal voltage having two different levels at a desired repetition period is supplied to the linear motor through a servo amplifier to drive the linear motor, and at the same time, the signal voltage is applied to a claw that engages with the perforation of the film. A light emitting element connected to the linear motor movable coil and constantly emitting light is moved, and this light emitting element operates a photoelectric potentiometer to obtain a voltage corresponding to the movement of the pawl, and this voltage is applied to the above servo. This device is characterized in that the moving coil of the linear motor is intermittently reciprocated by providing negative feedback to the amplifier, thereby intermittently feeding the film.

The present invention will be described in detail below with reference to the drawings.

FIG. 1 is a diagram showing the structure of an example of a film feeding mechanism of an 8 mm camera for carrying out the film feeding method of the present invention. The oscillator 1 generates a rectangular waveform signal as shown in FIG. 2 as an output. As will be described later, the repetition period T of this output waveform can be changed.
The output signal of this oscillator 1 is divided into two parts and supplied to a non-inverting amplifier 2 and an inverting amplifier 3, respectively, and the outputs of these amplifiers 2 and 3 are respectively sent to light emitting diodes 4 and 5 in a photoelectric potentiometer 33. supply
Therefore, during the period T ₁ in FIG. 2, the light emitting diode 4 is turned on, and the light emitting diode 5 is turned off, and the situation is reversed during the period T ₂ . photoelectric potentiometer 2
2 further includes a resistor layer 6, a photoconductive layer 7, and a photoconductive layer 8.
When one light emitting diode 4 is lit, only the vicinity of this light emitting diode 4 is irradiated, and when the other light emitting diode 5 is lit, only the vicinity thereof is irradiated. The resistor layer 6 and the conductive layer 8 are short-circuited at each position. Further, the positions of the light emitting diodes 4 and 5 and the photoconductive layer 7 are fixed at a prescribed interval from each other, and a prescribed voltage V _c is applied between both ends of the resistor layer 6. Therefore, during the period T ₁ in FIG. 2, that is, when only the light emitting diode 4 is lit, only the photoconductive layer 7 near the diode 4 is conductive, and the partial voltage l ₁ V _c of the resistor layer 6 at that position is A voltage is applied to the conductive current layer 8 . Further, l ₂ V _c (l ₂ <l ₁ ) is applied to the conductor layer 8 when the light emitting diode 5 is lit. The conductive layer 8 is connected to a non-inverting input terminal 24 of a servo amplifier 9, and the output of the servo amplifier 9 is supplied to a moving coil (not shown) of a linear motor 10 to linearly drive the motor 10. do.
A claw 11 for scraping off the perforated film is attached to a support plate 17 so as to be rotatable about a fulcrum 13, and a spring 16 causes the claw 11 to always scrape off the film 1.
Let it be pressed against 2. Attach the support plate 17 to the moving coil of the linear motor 10, and
1. The support plate 17 moves together with the moving coil when the linear motor is driven. Since the claw 11 is always pressed against the film 12, when it moves in the direction of arrow B in FIG. 1, it catches the film perforation and sends the film 12 in the direction B. Further, the strength of the spring 16 is set so that when moving in the direction of arrow A, the tip of the claw 11 is tilted so that the film 12 does not move out of the film perforation. A light emitting diode 18 is further fixed to the moving coil of the linear motor 10, and this light emitting diode moves along the photoconductive layer 20 of another photoelectric potentiometer 23 while maintaining a predetermined distance from the photoconductive layer 20. potentiometer 23
Place. Potentiometer 23 has a similar configuration to potentiometer 22. That is, it has a three-layer structure of a resistor layer 19, a photoconductive layer 20, and a conductive layer 21, and when the light emitting diode 18 is turned on, only the vicinity of the photoconductive layer 20 is irradiated and conductive. The light emitting diode 18 is always turned on, and the same voltage _Vc as that of the potentiometer 22 is applied to both ends of the resistor layer 19.
A voltage of X/lV _c is made to appear on the conductive layer 21 depending on the position X of the light emitting diode, where l is the total length of the light emitting diode. Further, the voltage appearing on the conductive layer 21 is applied to the inverting input terminal 25 of the servo amplifier 9 for negative feedback.

When the oscillator 1 is activated, during the period _{T 1} shown in FIG _. An output voltage corresponding to the difference between the voltage X/lV _c appearing on the conductive layer 21 of move to. When the moving coil of the linear motor 10 moves in the B direction, the light emitting diode 18 moves in the B' direction accordingly and the position X increases, so that the voltage X/lV _c generated in the conductive layer 21 increases. Therefore, the difference between the voltages applied to the inverting input terminal and the non-inverting input terminal of the servo amplifier 9 decreases as the moving coil of the linear motor moves in the B direction, and therefore the light emitting diode 18 moves in the B' direction. When X/l=l ₁ , the output voltage of the servo amplifier 9 becomes zero, the movement of the moving coil stops, and this state remains until the start of the period _T2 . During this stop period, the shutter is opened and the film 12 is exposed.

Furthermore, when the period T ₁ ends and the period T ₂ begins, the light emitting diode 5 lights up and the voltage of l _{2 Vc} is applied to the non-inverting input terminal 24 of the servo amplifier 9, and the voltage applied to the inverting input terminal 25 , that is, a voltage corresponding to the difference from l ₁ V _c is obtained as the output voltage of the servo amplifier. As mentioned above, since l ₁ V _c > V _c , this voltage becomes a negative voltage, and therefore the moving coil of the linear motor 10 moves in the direction opposite to the T ₁ period, that is, in the direction of arrow A, and the light emitting diode 18 moves in the direction of arrow A' and the position X decreases.
Correspondingly, the voltage X/lV _c obtained across the conductive layer 21 of the photoelectric potentiometer 23 gradually decreases from the voltage at the beginning of the period T ₂ , that is, l ₁ V _c , and the voltage The difference between the voltages applied to the inverting input terminal 25 and the non-inverting input terminal 24, that is, the difference between X/lV _c and l ₂ V _c gradually decreases, and the negative output voltage of the servo amplifier decreases accordingly, causing light emission. It becomes zero when the diode 18 is at the beginning of the period T ₁ , ie, when X/l=l ₂ . Therefore, at this point, the movement of the linear motor 10 in the A direction stops.

In this way, the reciprocating motion of the claw 11 is obtained, but as mentioned above, the film 12 is fed only when the claw moves in the B direction, so that intermittent feeding of the film 12 in the B direction is realized. At this time, the moving coil of the linear motor 10 is not forcibly stopped by a stopper, but its movement is controlled by a drive signal, so no noise is generated.

As is clear from the above description of the operation, the film feed interval, that is, the stroke of the movement of the claw 11, is determined by appropriately adjusting the distance between the light emitting diodes 4 and 5 to adjust the values of the voltages l ₁ V _c and l ₂ V _c . By doing this, any desired value can be obtained, so it is easy to adjust so that exactly one frame is fed.

According to the method of the present invention, by changing the oscillation repetition period T of the oscillator 1, the film feeding speed can be easily changed.

Further, according to the present invention, the ratio of T ₁ and T ₂ can be easily changed, and thereby the film stop time can be changed depending on the shutter opening time. For example, the film stop time can be changed depending on the shutter opening time. can be made equal to the opening time of For this reason, when the shutter opening angle is made variable, when the shutter opening angle is narrowed, that is, when the shutter opening time is shortened, the film stopping time can be shortened accordingly, and this makes it possible to scrape off the film. The frame feed speed can be increased while the speed itself remains unchanged.

Furthermore, according to the method of the present invention, mechanically, linear motion,
Since there are few mechanical mechanisms such as a circular motion conversion mechanism, the generation of noise is extremely low, making it particularly suitable for recording.

Furthermore, according to the method of the present invention, by using the power supply voltage V _c in common for the two photoelectric potentiometers 22 and 23, even if there is a fluctuation in this power supply voltage, it is automatically compensated for, thereby increasing the accuracy of positioning. etc., and allows accurate operation.

Further, according to the method of the present invention, since there is no sliding part in the photoelectric potentiometer 23, it is advantageous in terms of life span, noise, etc.

The present invention is not limited to the above-mentioned examples, but can be modified and modified in many ways. For example, the output of the oscillator can be directly supplied to the servo amplifier 9 by omitting the amplifiers 2 and 3 and the photoelectric potentiometer 22. The pawl mechanism connected to the moving coil of the membrane linear motor 10 can be of various types. Furthermore, the resistance value of the resistor layer 19 of the photoelectric potentiometer 23 is not distributed uniformly in the longitudinal direction, but is distributed non-linearly.
It is also possible to supply a desired drive signal. Furthermore, photoelectric potentiometers 22, 23
A lamp or the like may be used instead of the light emitting diode provided in the light emitting diode.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the overall configuration of the system of the present invention, and FIG. 2 shows an output waveform of an oscillator that drives a light emitting element. 1... Oscillator, 4, 5, 18... Light emitting diode, 9... Servo amplifier, 10... Linear motor, 11... Film feeding claw, 22, 23... Photoelectric potentiometer.

Claims (1)

[Claims] 1. Supplying a signal voltage having two different levels at a desired repetition period to the linear motor through a servo amplifier to drive the linear motor,
A light emitting element connected to the claw that engages with the perforation of the film and constantly emitting light in conjunction with a moving coil of a linear motor is moved, and a photoelectric potentiometer is actuated by this light emitting element to respond to the movement of the claw. The film feeding method is characterized in that the moving coil of the linear motor is intermittently reciprocated by obtaining a voltage and feeding the voltage negatively to the servo amplifier, thereby feeding the film intermittently. method. 2. A signal voltage having the two different levels at a desired repetition period is applied to two light emitting elements arranged at an appropriate interval of a photoelectric potentiometer to alternately blink at a desired repetition period and at a desired time ratio. 2. The intermittent film feeding method according to claim 1, wherein the intermittent feeding of the film is caused to occur.