JPH0511163A - Lens moving mechanism for camera - Google Patents

Abstract

PURPOSE:To easily recognize sensitively the motor-driven operation of a lens. CONSTITUTION:A focusing ring 12 is fitted to the recessed groove 11 of a lens barrel in such a state where it can slide and turn, and a comb-shaped pattern ring 13 formed by a notch is fixed on the one end of the ring 12 in a ring state. A pair of photointerrupters 14 and 15 is attached to the turning area of the pattern ring 13 at the half interval of the notch. The output patterns of the pattern ring 13 which are detected by the pair of photointerrupters 14 and 15 are respectively changed by two steps, furthermore, they off set by one step each other. By the use of the output pattern, the rotating direction and the rotating angle of the focusing ring 12 are detected. Consequently, the motor-driven moving means of the lens can be operated by the same sense as the case of a still camera.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens barrel of a camera, especially a video camera, in which a photographing distance is electrically adjusted.

[0002]

2. Description of the Related Art Conventionally, when it is attempted to adjust a shooting distance at the time of shooting with a video camera to shoot at a distant position or a close position, a switch provided on a side surface or the like of a video camera body is used to drive an electric motor. I was moving the lens. This switch is, for example, a seesaw-type switch, one of which constitutes a long-distance photographing switch and the other of which constitutes a short-distance photographing switch, and when either one of the switches is pressed, the motor is driven only while the switch is pressed. The lens can be moved in the desired direction. Then, the photographer observing the subject through the viewfinder releases the switch when the desired photographing distance is reached, so that the lens is stopped and the desired photographing distance is obtained.

[0003]

However, the method of adjusting the moving direction and the moving amount of the lens by simply pressing the switch has a drawback that it is difficult for the photographer to perceive the lens moving amount. Therefore, it is difficult to accurately move the lens to the desired shooting distance and stop at that position with a single switch operation, and move the lens back and forth several times near the desired stop position to move the lens to the desired position. Many adjustments were required and the operation was complicated.

In view of the above problems, the present invention electrically moves a lens by rotating a focus ring like a still camera in which the lens is manually moved, and the photographer can intuitively determine the amount of lens movement. An object of the present invention is to provide a lens moving mechanism of a camera that is easy to recognize.

[0005]

According to the present invention, there is provided a lens moving mechanism for a camera, in which the master lens in the lens barrel is electrically moved by a motor to adjust the photographing distance. In addition to the rotatably supported manual focus ring, the first detection means that rotates integrally with the focus ring, and the second detection means that is disposed in the rotation region of the first detection means, A fixed pattern to be detected is arranged on one side of the second detecting means, and a detection member for detecting the pattern to be detected is arranged on the other side of the second detecting means. Identify the rotation angle,
It is characterized in that the control means determines the drive direction and drive amount of the motor.

[0006]

When the focus ring is rotated to adjust the shooting distance at the time of shooting, the first detection means also rotates together, so that the detected pattern is detected as an output pattern with the second detection means fixedly arranged. Then, the rotation direction of the focus ring is detected, and the rotation angle is detected by counting or measuring this output pattern. Based on this, the drive direction and drive amount of the motor are determined and the desired lens is selected. The camera is moved to the position and the shooting distance is adjusted.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a schematic sectional view of a lens barrel of a video camera, in which 1 is a fixed frame of the lens barrel and 2 is a fixed frame.
Is a first fixed lens group 3 supported by the fixed frame 1 on the object side,
The first guide shaft 4, which is fixed to the rear side of the fixed frame 1 in the vicinity of the inner surface thereof and parallel to the optical axis, is slidably supported by the first guide shaft 3 and is an actuator (not shown) in the lens barrel. The movable lens group 5 driven by the second fixed lens group 5 is fixed to the rear of the movable lens group 5, and the second fixed lens group 6 is fixed to the image surface side behind the movable lens group 5 in the vicinity of the inner surface of the fixed frame 1 in parallel with the optical axis. The guide shaft, 7 is a master lens group slidably supported by the second guide shaft 6 by a support frame 7a,
Reference numeral 8 denotes a rotary shaft pivotally mounted on the fixed frame 1 in parallel with the second guide shaft 6 and screwed into the screw hole 7b of the support frame 7a, and 9 denotes a pinion shaft 9a screwed to one end of the rotary shaft 8. Is a motor capable of moving the master lens group 7 forward and backward in the optical axis direction by driving. In the lens barrel of this video camera, focus adjustment is performed by a master lens group 7 driven by a motor 9.

Reference numeral 11 denotes an annular groove formed on the outer peripheral surface of the fixed frame 1, 12 denotes a manual focus ring fitted in the groove 11 so as to be slidably rotatable, and 13 has an annular shape and one end has a focus. Fixed to the ring 12 with a notch 1 at the free end
3a is a pattern ring formed in a comb shape at equal intervals over the entire circumference, and 14 and 15 are arranged in parallel in the rotating region of the pattern ring 13 in the concave groove 11 so that the notches 13a of the pattern ring 13 can be detected. The first and second photo interrupters (see FIG. 2) are mounted on the substrate 14a.

When the focus ring 12 is manually rotated, the pattern ring 13 is also integrally rotated, and the photo interrupters 14 and 15 detect the notch 13a and when light reaches the light receiving element from the light emitting element. A HIGH signal is output, and a LOW signal is output when light is blocked by the tooth surface of the pattern ring 13 between the notch 13a and the adjacent notch 13a. Moreover, the two photo interrupters 14 and 15 are, for example, as shown in FIG.
One of the notches 13a in the rotation direction of the pattern ring 13
It is assumed that they are juxtaposed at intervals of 2.

Therefore, in FIG. 3, the interval between the photo interrupters 14 and 15 is set as one step of the rotation of the focus ring 12 with respect to the concave groove 11, and the first and second photo interrupters with respect to the notch 13a of the pattern ring 13 are formed. Assuming that the positions of 14 and 15 are indicated by alternate long and short dash lines as shown in the drawing, the outputs of the photo interrupters 14 and 15 are output in accordance with the right rotation and the left rotation of the focus ring 12, respectively, as shown in FIGS. ), Every two steps, and one step apart from each other, HIGH or LOW
Signal will change. That is, as is apparent from FIG. 3, when the pattern ring 13 rotates to the right, the first photo interrupter 14 outputs first, and when it rotates to the left, the second photo interrupter 15 outputs the output signal first. Is converted.

Then, the HIGH or LOW signals output from the first and second photo interrupters 14 and 15 are input to a control circuit (not shown), and in this circuit, based on these signals, the rotation direction of the focus ring 12 and The rotation angle is detected, the drive direction and drive amount of the motor 9 are determined, and a drive signal is output to move the master lens group 7 a desired distance.

Since this embodiment is constructed as described above, when the photographer adjusts the focal length while looking through the viewfinder, the master lens group 7 is moved back and forth by rotating the focus ring 12 with one hand. Let

For example, it is assumed that the focus ring 12 needs to be rotated to the right when shooting a long distance. In this case, when the focus ring 12 is manually rotated to the right, the pattern ring 13 rotates in the same direction with respect to the first and second photo interrupters 14 and 15, and both photo interrupters 14 between the first and second steps. , 15 outputs are both HIGH
However, only the first photo interrupter 14 changes to LOW during the second to third steps. Then, between each step, as shown in FIG.
The output signals of 4 and 15 change, and the conversion of the output signal of the first photo interrupter 14 is always faster than that of the second photo interrupter 15 in the right rotation. Therefore, the control circuit detects this to detect the rotation direction of the focus ring 12, and determines the driving direction of the motor 9 as the direction in which the master lens group 7 is extended.

Moreover, in FIG. 4A, the output signals of the first and second photo interrupters 14 and 15 are alternately switched to HIGH or LOW at each step, so that the control circuit counts them. Focus ring 1
The rotation angle of 2 is detected, the drive amount of the motor 9 is determined, the extension amount of the master lens group 7 is set, and a drive signal is output. Therefore, when the focus ring 12 is rotated rightward, the motor 9 is driven almost at the same time, the master lens group 7 is extended corresponding to the step angle of the focus ring 12, and the photographing distance is adjusted. ..

On the other hand, in the case of close-up photography, on the contrary, the focus ring 12 needs to be rotated, for example, to the left, and this time the pattern ring 13 is rotated to the left. Therefore, the first and second photo interrupters 14 and 15 are used. Contrary to the case described above, the output signal of the second photo interrupter 15 is first converted into LOW or HIGH as shown in FIG.
The rotation direction of 2 can be detected.

Therefore, when the focus ring 12 is rotated to the left, the motor 9 is driven at the same time, and the master lens group is retracted corresponding to the step angle of the focus ring 12 to adjust the photographing distance. Done.

As described above, according to the present embodiment, the master lens group 7 can be electrically moved by a required amount in any direction by manually rotating the focus ring 12, so that the shooting distance can be adjusted with a sense of a still camera. It is possible to sensuously recognize the moving direction and the moving amount of the lens, which facilitates the adjustment.

Although the notch 13a is provided as the detected portion of the pattern ring 13 in the above-described embodiment, a hole may be formed instead of the notch 13a. The lens barrel is not necessarily limited to the inner focus type, and it goes without saying that other types can be applied as long as the lens is moved electrically to adjust the shooting distance. Further, the number of photo interrupters is not limited to two, and for example, three photo interrupters are provided,
You may make it arrange | position at intervals of 1/3 of one notch 13a.

Next, FIGS. 5 and 6 show a second embodiment of the present invention, in which the pattern ring 13 has a notch 1
Instead of 3a, reflectors 17 are provided at the same intervals to form a fixed pattern. Also, photo interrupter 1
A pair of detection elements 20 including a light emitting element 18 and a light receiving element 19 as shown in FIG. 6 instead of the photo interrupters 14, 1 are provided in the rotation region of the pattern ring 13.
5 are arranged at the same intervals.

As shown in FIG. 7, the reflection plate 17 is not arranged on the pattern ring 13, but this portion is formed as a notch 13a or a hole, and the detection element 20 is sandwiched by the pattern ring 13.
It may be fixedly arranged in a ring shape at a position on the concave groove 11 opposed to.

Further, as shown in FIG. 8, the reflection plate 17 may be formed on the pattern ring 13 in a comb-teeth shape like the above-mentioned cutout 13a.

FIG. 9 shows a third embodiment of the present invention, in which the detecting means is a magnetic encoder.
That is, at one end of the focus ring 12, a magnetic drum 22 having a magnetic pattern formed by arranging unit magnetic materials 22a continuously so that both poles are located in the same direction of rotation is fixed, An MR element (magnetoresistive effect element) 23 having a pair of output terminals 24a and 24b is arranged near the rotating region of the magnetic drum 22. Moreover, M
The magnetizing pitch of the R element 23 is set so that the pulse signals output from the respective terminals 24a and 24b have a phase difference of 90 °, and the interval of this phase difference is set as one step by a control means (not shown). Try to detect the output pattern.

Therefore, in this embodiment, the focus ring 1
The HIGH or LOW of the pulse signal output from the two output terminals 24a and 24b is converted every two steps (180 °) according to the rotation direction of 2, and the conversion is performed by one step as in the first embodiment. Since they are displaced, the rotation direction and the rotation angle can be detected as in the first embodiment.

Next, a fourth embodiment of the present invention will be described with reference to FIGS. FIG. 10 is an explanatory view of a main part of the detection means and the focus ring 12, which are disassembled, and FIG. 11 is a plan view of the main part of the detection means. In the figure, reference numeral 26 denotes a first contact 26a, a second contact 26b, and a third contact 26, which are attached to the back surface of the focus ring 12 and are separated into m-shaped free ends.
c is a conductive sliding contact, and 27 is a conductive pattern fixed to the concave groove 11 of the fixed frame 1 and in contact with the sliding contact 26. In this pattern 27, 28 and 29 are provided. Is a ring-shaped first comb-tooth shape, which is arranged opposite to the rotating region of the sliding contact 26, and in which notches 28a and 29a and teeth 28b and 29b having the same interval in the longitudinal direction are alternately formed in a comb-tooth shape. The first and second comb-tooth patterns 28 and 29 are such that the first contact 26a and the third contact 26c are in contact with each other at the positions of the teeth 28b and 29b, respectively. Moreover, the two comb-shaped patterns 28, 29 are half of the notches 28a, 29a.
It is arranged in the rotational direction by the width of. Reference numeral 30 denotes a ring-shaped linear pattern which is arranged between the patterns 28 and 29 in parallel with the patterns 28 and 29 and which is always in contact with the second contact 26b. In addition, one end of each of the comb-teeth patterns 28 and 29 is grounded.

Then, 31 is a power source connected to the linear pattern 30, 32 is the first and second comb-shaped patterns 28, 2
The counter circuit 9 is connected to the control circuit 9 and is connected to a control circuit (not shown) together with the power supply 31.

Therefore, the first contact 26a of the sliding contact 26 is
Is in contact with the teeth 28b of the first comb-toothed pattern 28, the first comb-toothed pattern 28 and the linear pattern 30 are in a conductive state, and are in a non-conductive state at the position of the cutout 28a. HIGH when the power is on, L when the power is off
It is assumed that an OW signal is output. This is the third contact 2
6c is a tooth 29b and a notch 29 of the second comb tooth-shaped pattern 29.
The same applies to the case of being located on a. Moreover, since the first comb-tooth pattern 28 and the second comb-tooth pattern 29 are displaced from each other in the rotational direction by a width of ½ of the notch, this detecting means is the first embodiment shown in FIGS. 3 and 4. An output pattern identical to the output pattern of is obtained.

Since this embodiment is constructed as described above, when the focus ring 12 is rotated, the sliding contact 26 is, for example, as shown in FIG. 11 with respect to the first and second comb-shaped patterns 28 and 29. In the position shown in (1), the output signal of HIGH for the first comb tooth pattern 28 and the output signal of LOW for the second comb tooth pattern 29 are input to the counting circuit 32. When the sliding contact 26 rotates to the right or left in the figure, the output signals obtained from the circuits of the first and second comb-shaped patterns 28 and 29 have the same pattern as in the first embodiment. Therefore, the rotation direction and the rotation angle of the focus ring 12 can be detected as in the first embodiment.

In this embodiment, unlike the above case, the first and second comb tooth patterns 28, 29 are attached to the focus ring 12 and rotated, and the sliding contact 26 is fixedly arranged on the fixed frame 1. However, it is not preferable because the wiring side is rotated.

Next, FIGS. 12 and 13 show a fifth embodiment of the present invention, in which a sliding contact 34 having a set of contacts 34a and 34b is attached to the rear surface of the focus ring 12 while fixed. In the rotating region of the sliding contact 34 on the groove 11 of the frame 1, the resistance pattern 35 with which the contact 34a contacts.
And a ring-shaped conductive pattern 37 composed of a linear pattern 36 with which the contact point 34b contacts is fixedly arranged. Both ends of the resistance pattern 35 in the ring-shaped longitudinal direction are separated from each other, and one end thereof is grounded.

Therefore, both patterns 35 and 36 form a circuit which is always energized with the sliding contact 34, and when the focus ring 12 rotates, the energization area of the resistance pattern 35 changes to increase or decrease the resistance. Since the output pattern detected by the detector (not shown), that is, the potential increases or decreases as shown in FIG. 13, the rotation direction of the focus ring 12 can be detected by the increase or decrease of the potential. Further, the rotation angle can be detected by detecting the increase or decrease of the voltage value.

Also in this embodiment, the conduction pattern 37 may be attached to the focus ring 12 and the sliding contact 34 may be fixedly arranged on the fixed frame 1. A change in current may be detected instead of the voltage.

14 and 15 show a modification of the fifth embodiment, which will be described as a sixth embodiment. In this embodiment, the endless ring-shaped resistance pattern 3 is used.
9 is arranged in the concave groove 11 and is grounded, and ring-shaped linear patterns 40 and 41 are arranged on both sides thereof to form a conduction pattern 42. Then, two sliding contacts 43, 44 are attached to the back surface of the focus ring 12 at positions slightly displaced in the rotational direction, and one of the sliding contacts 43, 44 has a linear pattern 40, 41, respectively.
, And the other contact is also in contact with the resistance pattern 39. Therefore, the output patterns, that is, the potentials detected by the detectors (not shown) of the two circuits are slightly different from each other depending on the positions of the sliding contacts 43 and 44.

In the case of this embodiment, the focus ring 12 can be rotated 360 ° endlessly, and the potential patterns of the two circuits detected by the respective detectors are as shown in FIG. Is 0 °, the maximum value is reached when the sliding contacts 43, 44 reach the position of 180 °.
It becomes 0 at 360 °. Therefore, in each circuit, 360
The same potential appears in two places in the region of °. for that reason,
In this case, even if one sliding contact is arranged as in the fifth embodiment described above, the rotation direction cannot be detected even if the potential value rises and falls. Therefore, by arranging the two sliding contacts 43 and 44 with a slight shift as in the present embodiment, it is possible to detect which of the sliding contacts contains the detected potential higher than the potential of the other circuit. By focus ring 1
The rotation direction of 2 can be detected. Then, it is possible to determine whether the angular position is larger or smaller than the 180 ° position by detecting whether the potential changes in the increasing or decreasing direction, and further to detect the rotational angular position from the amount of change in the electric potential. Become.

Also in this embodiment, the conduction pattern 42 may be attached to the focus ring 12 and the sliding contacts 43 and 44 may be fixedly arranged on the fixed frame 1.

The present invention can be applied not only to video cameras but also to still cameras equipped with a manual electric focus adjustment mechanism. Further, the pattern ring 13, the first and second photo interrupters 14 and 15, the reflection plate 17, the pattern ring 13, the detection element 20, the magnetic drum 22 and the MR element 2
3, the sliding contact 26 and the conduction pattern 27, and the sliding contacts 34, 43 and 44 and the conduction patterns 37 and 42 respectively constitute a first detection means and a second detection means.

[0036]

The lens moving mechanism of the camera according to the present invention comprises the first detecting means which rotates integrally with the focus ring, and the second detecting means which is arranged in the rotation area of the first detecting means. Therefore, by rotating the focus ring, it is possible to electrically move the lens for adjusting the shooting distance, which is an important practical advantage that the lens moving direction and the moving amount can be easily perceived.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing a first embodiment of a lens moving mechanism of a lens barrel according to the present invention.

FIG. 2 is an exploded perspective view of a main part of the lens barrel showing an arrangement relationship between a pattern ring and a photo interrupter with respect to the lens barrel of FIG.

FIG. 3 is a plan view of relevant parts showing a moving position for each step to the right with respect to an end portion having a notch of a pattern ring.

FIG. 4A is a table showing the output signal of each step of the first and second photointerrupters when the pattern ring is rotated to the right, and FIG. 4B is the pattern ring which is also rotated to the left. It is a table when it is made to.

FIG. 5 is a principal part explanatory view showing a positional relationship between a pattern ring and a detection element according to the second embodiment of the present invention.

FIG. 6 is an explanatory diagram showing a relationship between a detection element and a reflection plate.

FIG. 7 is a view similar to FIG. 6 showing a modification of the second embodiment.

FIG. 8 is a diagram showing another modification of the pattern ring of the second embodiment.

FIG. 9 is an explanatory view of a main part showing a third embodiment of the present invention.

FIG. 10 is an explanatory view of a main part showing a fourth embodiment of the present invention.

FIG. 11 is a plan view of a main part of a detecting means according to a fourth embodiment.

FIG. 12 is an explanatory view of a main part showing a fifth embodiment of the present invention.

FIG. 13 is a diagram showing a change in potential depending on a rotation angle of a focus ring.

FIG. 14 is a main part plan view showing a sixth embodiment of the present invention.

FIG. 15 is a diagram showing a change in potential according to a rotation angle of a focus ring.

[Explanation of symbols]

 7 Master Lens Group 9 Motor 12 Manual Focus Ring 13 Pattern Ring 13a Notch 14 First Photointerrupter 15 Second Photointerrupter 17 Reflector 20 Detecting Element 22 Magnetic Disk 23 MR Element 26, 34, 43, 44 Sliding Contact points 27, 37, 42 Conduction pattern 28 First comb-tooth pattern 29 Second comb-tooth pattern 38, 39 Resistance pattern

Claims (1)

Claim: What is claimed is: 1. A camera in which a lens in the lens barrel is moved by a motor to adjust a shooting distance, and a manual focus rotatably supported by the lens barrel. A ring, a first detection unit that rotates integrally with the focus ring, and a second detection unit that is arranged in a rotation region of the first detection unit, and one of the first and second detection units is provided. Is provided with a detected pattern, and the other is provided with a detection member for the detected pattern. Based on the output patterns from both detection means, the rotational direction and the rotational angle of the focus ring are identified to identify the motor. A lens moving mechanism characterized in that a driving direction and a driving amount are determined.