JPS59123823A - Power focus device - Google Patents

Abstract

PURPOSE:To execute an exact focusing in a short time by interlocking the comparative length of an operating time of a power focus device and the magnitude of the focus shift amount. CONSTITUTION:In case a focus does not conform to the rear focus direction, a lens is driven to the front focus by a switch S2. It is executed by phi reset of a counter 6, an H level input to an AND gate 9, a motor M4, etc. If a photographer pushes the S2 continuously, the M4 rotates continuously through a prescribed circuit. When the photographer confirms the focusing and turns on an S3 in addition to the switch S2, the M4 stops. When it is desired to execute a fine adjustment by rotating the M4 in reverse by delaying the operation for depressing the S3, if the S3 is turned on and the S2 is turned off, on the contrary, a counter 7 is reset, the M4 rotates in reverse impulsively, and the fine adjustment can be executed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power focusing device that drives a camera lens for focusing using a motor controlled by a manual switch.

Conventionally, a device that drives a lens using an electric motor has a length of 8 m.
Power zoom devices for cameras are known. The power zoom device was equipped with two switches, one for increasing the focal length and one for decreasing the focal length, and was configured to operate the power zoom by turning all of the switches on and off.

The photographer turns on the switch while checking the zoom operation in the viewfinder, energizes the motor KL, and when the desired angle of view is achieved, turns off the switch to stop the zoom operation. However, even if the photographer confirms the desired angle of view in the viewfinder and turns off the switch,
There is a very short delay between confirmation and turning off the switch, although this varies depending on the photographer.

In the case of a power zoom device for an 8-point camera, even if this delay occurs, the angle of view only changes slightly and there is no problem. However, when applying the above-mentioned power zoom device for an 8 mm camera to a power focus device that uses a motor to drive the lens for focusing, when a long focal length lens is used as the photographing lens, the aperture is opened wide. When the depth of field is shallow and focusing is difficult, the lens stop position shifts due to the delay, making it difficult to accurately focus. Therefore, it is necessary to repeat the focusing operation to adjust the focus, which has the drawback of extremely poor operability.

In view of this point, the present invention aims to eliminate the above-mentioned drawbacks and realize a power focusing device with good operability.

The present invention will be described in detail below using the drawings.

FIG. 1 is a circuit diagram of a control circuit according to an embodiment of the present invention, and FIG. 2 is a chart of inputs and outputs of the control circuit according to this embodiment. In Figure 1, 1 is a power supply battery, 2 is a switch that drives the lens toward the front focus, 3 is a switch that drives the lens toward the back focus, 4 is a motor that drives the lens, and 5 is an oscillation frequency of several hertz. The generating oscillators 6 and 7 are counters having a reset terminal R1, a count input terminal CI, and an output terminal CO, and are reset by a turntable (not shown) when the power is turned on. 8, 9, 10° are and gates, 12, 13
, 14.15 are reverse current prevention diodes, 16, 17,
18 and 19 are transistors that control the current flowing to the motor 4, and 20 and 21 are inverters. 2g in Figure 2.

3S is a chart showing the on/off state of the switch 2, 3S is a chart showing the on/off state of the switch 30, 48 is a chart showing the driving state of the motor 4, and 5S is a chart showing the output of the oscillator 5.

Next, an embodiment of the present invention constructed as described above will be described.

When a photographer takes a picture, he or she looks at a viewfinder (not shown) and, for example, if the camera is out of focus in the rear direction, the photographer can drive the lens in the front focus direction.
When the switch 2 for driving the lens in the front focus direction is turned on, a signal at the reset terminal RKH level of the counter 6 is input, and the counter 6 is reset to φ.

At the same time, the H level is input to the AND gate 9, so a lens drive signal synchronized with the oscillation signal from the oscillator 5 turns on the AND gate 9, diode 13, and block 18A. Therefore, the motor 14 is rotated as shown in FIG. 248 in synchronization with the oscillation signal so as to drive the lens toward the front focus.

The lens drive signal synchronized with the oscillation frequency of the output of the AND gate 9 is also input to the AND gate 11, and the counter 7 is reset by a reset circuit (not shown) when the power is turned on. If this continues, the output of the carry terminal becomes L level, and the input of AND gate 110 becomes H level via inverter 21. As a result, the output of the AND gate 11 synchronized with the oscillation signal of the AND gate 9 is input to the count terminal CI of the counter 7, and the output of the AND gate 11 is counted a predetermined number of times and the output of the AND gate 11 is input to the count terminal CI of the counter 7.
The output terminal CO becomes H level. Before the output of the output terminal CO of the counter became H level, the transistor 181711, which had been turned on in synchronization with the oscillation signal, was continuously turned on by the H level signal of the carry terminal of the counter, and the motor 4 was turned on. It rotates continuously and focuses continuously. The photographer confirms that the photographic lens is in focus within the 7-inder mode, and then presses the switch 2 again.
In addition, when switch 3 is turned on, the output of AND gate circuit 8°89 is synchronized with the oscillation signal of oscillator 5, so the base inputs of transistors 6.1, 7, 18, and 19 are also all synchronized, and transistors 16.17 18 and 19 are all turned off, and the rotation of the motor 4 is stopped.

As a result of the photographer's delay in pressing the switch 3 to stop the motor 14, if the motor 14 needs to be rotated in the reverse direction for fine adjustment, it is necessary to leave the switch 3 on and turn off only the switch 2. In this case, in contrast to the above, the counter 7 is reset, the output of the AND circuit 8 synchronizes the oscillation signal, the transistors 16 and 19 are driven in pulses, and the motor is driven in pulses in the reverse rotation, thereby making it possible to perform fine adjustment.

If one pulse of lens drive is within 3 degrees at the distance ring of the photographing lens, the amount of defocus of the image on the film surface will be about 10μ, so there will be no problem even if the fine adjustment is made in pulses rather than continuously. Accurate focusing can be achieved even if the lens is driven in pulses.

In this embodiment, the motor 4 is driven in pulses at startup and for a certain period of time thereafter, but if a low-speed, large-torque motor can be used, it is of course possible to drive the motor 4 at low speed at startup and for a certain period of time. Further, in the embodiment, the speed of the motor is controlled only at the time of startup and for a certain period of time thereafter, but the speed of the motor may also be controlled at the time of stopping and for a certain period of time before stopping. In that case, for example, the photographer turns on one or the other switch to drive the lens, and then, when the camera is close to focusing, the photographer can press both switches to create a cipulus or The control means may be configured to drive at low speed. This configuration can be realized relatively easily in this embodiment.

FIG. 3 is a block diagram of another embodiment of the present invention, and FIG. 4 is a time chart of another embodiment of the present invention. In Fig. 3, 1 is a power supply battery, 2 is a switch that drives the lens toward the front focus, 3 is a switch that drives the lens toward the back focus, and 2
0,21°22.23 are transistors that control the current flowing through each phase of the stepping motor, 26,27°28°
, 29 are the windings of each phase of the stepping motor, which will be described later.
0 is a winding of each phase of a stepping motor to be described later, 30 is a rotor of a stepping motor to be described later, 31 is the rotor,
A stepping motor formed from a winding wire and driving a distance ring of a photographing lens (not shown); 32 is a transistor 22 to 2;
A), terminal φ1.
φ2. φ3. φ4 are transistors 22 and 23.

Connected to 24.25. 35,36°37.38
are transistors 22, 23, 24.

25 base resistance.

Next, the operation of this embodiment will be explained.

For example, when moving the lens to focus in the front direction, press the front lens direction drive switch 2, and the microcomputer connects terminals φ, φ, φ3, . φ outputs a pulse according to the program.

That is, first, a signal from the H level to the L level is output to the terminal φ1, the transistor 22 is turned on, current flows through the winding 29 of the stepping motor 31, and the rotor 30 rotates by 1/4. Next, after a predetermined period of time, a pulse is output to the terminal φ, the transistor 23 is turned on, current flows through the winding 26, and the rotor 30 rotates by 1/4. microcomputer 3
Pulses are sequentially sent from terminal φ3.2 to terminal φ3.2. φ4. φ1. φ2゜ is 2
After the rotation, if the photographer continues to turn on switch 2, the microcomputer outputs terminal φ8. φ2.
φ1. The period of the pulse sent to φ4 is approximately 1/6 of the period of the first 8 pulses, and the pulse motor
If you rotate it at twice the speed, a and ' will be formed. The photographer confirms that the camera is in focus and presses switches 2 and 3 at the same time, causing the microcomputer to hold the pulse output and stop driving the stepping motor at that point.

In this embodiment, although a timer as a timer means is not shown in the drawings, it is realized by a clock and a counter within the microcomputer.

In addition, in this embodiment, the lens drive switch was turned on and the pulse motor 31 was driven with low frequency pulses only when it started to move, but by rewriting the program of the 2 microcomputer, the υ pulse motor 3 Even at the time of stopping the process, fine adjustment can be made using low frequency pulses instead of stopping from a state where the drive is performed using high frequency pulses as in the embodiment.

In this embodiment, a microcomputer is used as a control means for increasing the power supplied to the motor and increasing the rotational speed of the motor after a certain period of time has elapsed since the power focus device was activated. Specifically, a microcomputer was used as a control means to pulse the power supplied to the motor when starting the motor and for a certain period of time, and to change the rotational speed of the motor in a pulsed manner.

As described above, when the present invention is used, when the amount of defocus in the power focus device is small, the photographing lens is driven for a short time by turning on the switch of the power focus device for a short time, making it possible to make fine adjustments and correct the defocus. When the amount of light is large, the camera lens is driven continuously by keeping the power focus device switched on, allowing for quick lens drive and improved operability even when the depth of field of the camera lens is shallow. An excellent power focusing device can be realized. Furthermore, as a result of the improved operability, there is no need to perform unnecessary lens driving, thereby reducing the consumption of smearing force, which is extremely effective.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of an embodiment of the present invention, Fig. 2 is a time chart showing the practical operation of the present invention, Fig. 3 is a block diagram of another embodiment of the present invention, and Fig. 4 is a block diagram of the present invention. 12 is a time chart showing the operation of another embodiment. 1. Power battery, 2. Switch to drive the photographic lens toward the front bin, 3.
A switch for driving the photographing lens toward the rear bin, 5, an oscillator, 6, a counter, 32, a microcomputer.

Claims (1)

[Scope of Claims] (1) In a Power 7 Orcus device that drives a photographing lens with a motor, a timer means and a timer means are provided to supply the power to the motor after a certain period of time has elapsed since the Power Focus device is activated and the Power 7 Orcus device is in operation. A power focus device characterized by comprising control means for increasing electric power and increasing the rotational speed of a motor. (21% Scope of Claims The power 7 os device described in item ➝ is provided with a control means for changing the rotational speed of the motor in a pulsed manner by pulsing the electric power supplied to the motor at the time of starting the motor and during a certain period of time. (3) In the power focusing device according to claim 1, when the motor is stopped, the power supplied to the motor is reduced for a certain period of time before the motor is stopped. (4) A power focus device according to claim 1, characterized in that the power focus device includes a control circuit that pulses the power supplied to the motor when the motor is stopped and for a certain period of time before the motor is stopped. Device.