JPS6060048B2 - autofocus cinematography camera - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a movie camera having an automatic focus adjustment device, more specifically a camera having a zoom lens, which
The present invention relates to a camera that performs automatic focus adjustment using an automatic focus adjustment mechanism.

Autofocus cameras have been developed that optically scan the direction of a subject and automatically adjust an objective lens to a predetermined position according to a detected focus signal.

In order to realize such an autofocus camera,
It becomes necessary to provide a motor to provide the power to drive the mechanisms necessary for optical distance scanning and the power to drive the lens to the in-focus position. However, many motors are already used in movie shooting machines, and in particular, many cameras with a zoom lens are provided with a motor for driving the zoom lens. Furthermore, some cameras having a simultaneous recording device are provided with a motor that drives a capstan for simultaneous recording in addition to the normal film advance. In this way, current 8Tfrm camera systems often use a large number of motors, and the introduction of motors for automatic focus adjustment is completely contrary to the desire to make the entire camera smaller and lighter. . For this reason, there is an idea to use the capstan motor of a sound camera as an optical scanning motor, a so-called scan motor, but since the capstan motor is only installed in sound cameras, However, it is necessary to provide a separate motor.

Therefore, optical scanning is performed using a film drive motor that feeds the film in the aperture section. In other words, if the drive motor and the motor for optical scanning are used together, it becomes difficult to perform optical scanning before driving the film, and it is not possible to use the camera to confirm the distance to the subject before photographing. SUMMARY OF THE INVENTION An object of the present invention is to configure an autofocus camera capable of power zooming to be compact and capable of rational operation.

In order to achieve the above object, an automatic focus adjustment movie camera according to the present invention is a movie camera that performs automatic focus adjustment by photoelectrically detecting a subject position by comparing an image obtained by optical distance scanning with a fixed image. a motor for advancing the film; a motor for driving the focusing lens based on a subject position signal for automatic focus adjustment; and a cam mechanism for driving the scanning mirror, which is selectively coupled to the variable magnification ring by external operation. and a variable magnification lens drive motor to rotate the motor, and a circuit to control each motor.When shooting, first connect the power to the focusing motor and variable magnification ring drive motor, and then connect the power to the focusing motor and the circuit to control each motor. The motor is configured to be connected to a power source.

According to the above configuration, the object of the present invention can be completely achieved. The camera according to the present invention will be explained in more detail below with reference to the drawings and the like.

FIG. 1 is a schematic diagram showing the relationship between the scanning optical system and the module.

Light from the direction of the optical axis of the camera passes through a fixed mirror 2 to a module 3 for generating a focus signal at a photographing possible distance (MI
Light from the scanning mirror 1, which rotates back and forth in order to receive images from a distance closer than N) to an angle exceeding infinity (CK), is also introduced into the module 3, and those images are photoelectronically transmitted within the module. The subject signal F
is generated. FIG. 2 is a graph showing the subject signal F, in which the time axis t corresponds to the distance, and the first
A signal indicating that the subject is present at the position shown in Figure X is generated.

FIG. 3 is a graph showing a signal waveform indicating the current position of the photographic lens.

This signal is generated by a photoelectric switch SW7 and a scanning lever 23 provided on a lens position interlocking lever 25 that follows the movement of the photographing lens 9 shown in FIG. FIG. 3 shows that the objective lens is focused at the Y position and is offset from the object position x. FIG. 4 is a circuit diagram showing an embodiment of a circuit related to focus adjustment of a camera according to the present invention.

The control signal generation circuit 4 receives the synchronization signal S for the above-described object position signal F1 and lens current position signal W1 scanning. As will be described later, the synchronizing signal S sends out a high-level output every half cycle of optical scanning. According to these signals, signals indicating the direction and amount of movement of the lens, more specifically the focusing lens, are generated, and x shown in FIG.
A signal (A'AB'B) is generated to drive the motor Mp so that the positions of Y shown in the figure match.

Motor M.

is the motor for transporting the film, and the switch SWl
, SW2 are connected to the power source 36 and rotated. The motor M2 is a motor for driving a variable magnification lens for zoom photography, and is also used as a motor for optical scanning in this invention.

Switch SWl is on, switches SW4, SW5, S
When either W6 is on, it is connected to the power supply 36. A motor Mp is a motor for driving the focusing lens 9 for automatic focusing, and is connected to a bridge circuit formed by transistors 5, 6, 7, and 8.

The bases of the transistors forming this bridge circuit are respectively connected to the output terminals of the control signal generating circuit 4, and when B is at L level (A is at H level), transistors 6 and 7 are conductive and the first In the direction of , A becomes L level (B
is at H level), transistors 5 and 8 are turned on and rotated in the other direction. Furthermore, in order to enable the camera according to the present invention to simultaneously record sound, a motor for capstan drive is provided, and for automatic exposure adjustment, a meter or motor for driving an aperture is provided.

The switch SWl is a monitor switch and is linked to a trigger lever (not shown).

It is closed at the first part of the trigger lever stroke and forms its power supply if the camera has an exposure adjustment mechanism, and its power supply circuit and recording circuit if it has a capstan motor for simultaneous recording. This switch forms a state immediately before photographing or a state for checking whether or not photographing is possible. Switch SW2 is motor M for film feeding.

It is a switch that connects the switch to a power source, and is rotated in conjunction with a trigger lever so that it is turned on after the SW1 is turned on. The switch SW3 is a switch for selecting whether to use this camera for automatic focus adjustment shooting or to adjust the focus according to the photographer's will.

Switch SW for closing the circuit of zoom motor M2
6, and is closed simultaneously when the autofocus knob 31 is moved to the A side as shown in FIG. 5, and SW3 supplies power to the autofocus motor MF drive circuit and drive signal generation circuit. SW6 forms a circuit for the zoom motor Mz.

Switch SW4 is an electric zoom lever 28 shown in FIG.
This is a switch that is closed when the zoom motor M2 is moved upward (T side) and forms a circuit for the zoom motor M2.

The switch SW5 is similarly linked to the electric zoom lever 28, and is a switch that moves the zoom lever 28 downward (to the W side) and forms a circuit for the zoom motor M2.

Switch SW7 (see FIG. 5) is a photoelectric switch provided to generate a signal (W) indicating the current position of the lens.

Switch SW8 (see FIG. 5) is a switch provided to generate a synchronizing signal related to optical scanning, and is turned on and off by a cam 34 fixed to the shaft of zoom motor Mz, and generates a signal synchronized with optical scanning. (S) is generated.

FIG. 5 is a perspective view mainly showing an embodiment of the focus adjustment mechanism and zoom mechanism of the camera according to the present invention.

A focusing lens ring gear 10 is integrally provided with a focusing lens ring 9 that supports a focusing lens.

The output shaft of the focusing motor MF is connected to the gear 13,
12 and 11. The lens position interlocking lever 25 is urged forward by a spring 26 and is slidably supported above, and is pressed against the shoulder of the focusing lens ring 9 by a pin 25'' implanted at the tip. , moves forward and backward in accordance with the forward and backward movement of the focusing lens ring 9. The lens position interlocking lever 25 is provided with a photoelectric switch SW7.

The focusing zoom motor Mz is rotated so as to project in both directions, and the scanning cam 34 is fixed to one side.
4 is provided with a pin 35 that is eccentric to the rotation axis of the motor. This pin 35 is located at the center of the rotation axis of the scanning mirror 1.
A pair of rotatable scanning levers 23 are brought into contact with this, and as the motor rotates, the scanning lever 23
Rock 3. Note that the scanning lever 23 is biased clockwise in the figure by a spring 24. An arm 23'' protruding from the scanning lever 23 at a right angle S is connected to the photoelectric switch, moves in and out of the space between the opposing light emitter and photoreceptor provided in the switch, and adjusts the lens position. signal w
to occur. The scanning cam 34 has a synchronization signal switch SW8
is turned on and off to generate a synchronization signal S. A manual zoom lever 1 is attached to the variable magnification ring 14 that supports the variable magnification lens.
6 is fixed, allowing zoom photography other than power zoom. The variable power ring 14 has a variable power ring gear 15
are integrated. A worm gear 17 is coupled to the lower shaft of the motor M2, and its rotation is controlled by a spur gear 19 integrally coupled thereto via a helical gear 18.
transmitted to.

A rotary base plate 29 is rotatably provided on the base plate 27 about the axis of the spur gear 19, and spur gears 20, 21, and 22 are rotatably provided on the rotary base plate 29. gear 2
0 and gear 21 are rotated in opposite directions. A pin 295 is installed on the rotating base plate 29 and is connected to the power zoom knob 28. The power zoom knob 28 is supported so as to be movable in the vertical direction, and is supported by a spring 30.
It is always kept in a neutral position.

When the power zoom knob 28 is pushed up against the spring 30, the power zoom switch SW4 is closed, and the rotary base plate 29 is rotated counterclockwise to couple the gear 20 to the variable power ring gear 15. Spring 30 power zoom knob
When pressed down against this, the power zoom switch SW5 is closed and the rotary base plate 29 is rotated clockwise to connect the gear 22 to the variable magnification ring gear 15. The power zoom knob remains in the neutral position unless operated.
0 and 22 are not coupled to the variable power ring gear 15. A knob 371 that is slidably supported on the main plate 27 is a knob for switching between automatic focus adjustment and manual focus adjustment, and when this knob is moved to the A side in the figure, the autofocus switches SW3 and SW6 are switched. Close.

32 is a master lens, and 33 is a film.

The operation of the camera configured as described above is as follows. For auto focus photography, auto focus knob 3
1 to the A side and turn on auto focus switches SW3 and SW6. In this state, the control signal generating circuit 1 and the circuit formed by transistors 5, 6, 7, and 8 are not connected to the power supply. Next, when the trigger lever of the camera (not shown) is pressed, the switch SWl is turned on, and current is supplied to the circuit 1 and the transistor bridge circuit.

- The zoom motor M2 is connected to the power supply through the switch βW6 and starts rotating, and the scanning lever 2 is rotated by the rotation of the scanning cam 34.
3 is swung, and the scanning mirror 1 starts rotating for optical scanning. At the same time, the rotation of the eccentric pin 35 causes a synchronization signal S to be generated. Also, by swinging the scanning lever, a signal W indicating the current position of the focusing lens is sent to the photoelectric switch SW7.
generated from. These signals W, S and the subject position signal F from the module 3 are applied to the control signal generation circuit 4, which determines the direction and amount of movement of the focusing lens, and supplies current to the focusing motor Mp. .

The rotation of the focusing motor MF is transmitted to the focusing lens ring gear via gears 13, 12, and 11. In this state, the power zoom knob is in the neutral position, so gear 20
, 22 are not coupled to the gear 15, so the variable power lens is not driven.

When the trigger lever is further depressed and the film drive switch SW2 is turned on, the motor MD is connected to the power source, the film 33 is fed, and photographing by automatic focus adjustment is started. In this state, power zoom can be performed by moving the power zoom knob 28 to the T or w side.

When the gear 20 or 22 is coupled to the gear 15, the load on the motor Mz will increase, so the rotational speed of the motor Mz will change due to this increase in load, and the motor should be adjusted so that the optical scanning speed does not suddenly change. The ridge must have sufficient torque to perform power zoom.
When trying to determine the focus of the camera according to this embodiment according to the photographer's will, the autofocus knob 31 should be set to M.
When the switch SW3 and SW6 are moved in the direction of , the switches SW3 and SW6 are opened and no drive current is supplied to the motor MF.

The focus can be adjusted to any position by rotating the focusing lens ring 9. Further, when performing zooming that does not involve power zooming, it is sufficient to turn the lever 16. Since the camera according to the present invention uses the zoom motor M2 as an optical scanning motor, it is possible to perform automatic focus adjustment independently of the film drive without providing an optical scanning motor.

In other words, you can perform automatic focus adjustment in advance, check the condition, and then take a picture.

Further, since the power extraction for optical scanning and the power extraction for power zooming can be rationally configured as in the embodiment, an excellent effect can be obtained in that the entire camera can be made compact.

[Brief explanation of drawings]

Figure 1 is a principle diagram for explaining optical distance scanning, Figure 2 is a waveform diagram showing the subject position signal (F), Figure 3 is a waveform diagram showing the lens position signal (W), and Figure 4 is the main FIG. 5 is a circuit diagram showing an embodiment of a circuit related to focus adjustment of a camera according to the present invention. FIG. 5 is a perspective view mainly showing an embodiment of a focus adjustment mechanism and a zoom mechanism of a camera according to the present invention.

Claims (1)

[Claims] 1. In a movie camera that performs automatic focus adjustment by photoelectrically detecting the subject position by comparing an image obtained by optical distance scanning with a fixed image, a motor for advancing the film and an automatic focus adjustment are provided. a variable magnification lens drive motor selectively coupled to a variable magnification ring by external operation while rotating a cam mechanism for driving the scanning mirror; The circuit for controlling each of the motors is configured such that during automatic focus adjustment photography, a power supply is first connected to the focusing motor and variable magnification ring drive motor, and then a motor for film advance is connected to the power supply. An autofocus cinematography camera featuring: 2. The mechanism for selectively coupling the variable magnification lens drive motor to the variable magnification ring by external operation is an automatic mechanism according to paragraph 1, wherein the mechanism is configured to be able to form three types of states: neutral, forward, and backward. Adjustable focus cinematography camera.