JPH08160278A - Zooming movement controller - Google Patents

Abstract

PURPOSE: To detect the zooming position just after turning on a power source by a simple structure. CONSTITUTION: A position display body 20, on which recessed parts A, C, E, G and projected parts B, D, F, H having different lengths in the circumferential direction are alternately formed, is arranged on a cylinder 7. A photointerruptor 21 for detecting the recessed parts A, C, E, G or the projected parts B, D, F, H of the position display body 20 is provided. When a power source is turned on, the cylinder 7 is rotated to the telescopic end or the wide-angle end. During a time interval from the detection of neighboring recessed parts A, C, E, G or the projected parts B, D, F, H to the detection of the next recessed parts A, C, E, G or projected parts B, D, F, H by means of the photointerruptor 21, driving pulses to a stepping motor 16 are counted by a rotating amount detecting means 19. From a number of pulses at this time, the current zooming position is recognized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a zoom movement control device for varying the position of a lens in an optical device such as a microscope or a camera for performing zooming (variable magnification) control and focusing control.

[0002]

2. Description of the Related Art Conventionally, zooming in a zoom lens such as a microscope or a camera is generally performed by rotating a barrel engaged with a lens barrel by a cam mechanism to move a plurality of lenses mounted in the barrel back and forth. Since the zoom position information at this time is indispensable as a parameter for shooting control such as determination of the focal length and control of the aperture, when zooming is performed, the zoom position information is changed. It is designed to detect.

In order to detect this zoom position,
In Japanese Patent Laid-Open No. 5-53039, pulse generation means for generating a number of pulses corresponding to the amount of rotation of the cylinder as lens movement amount information, and a switch provided at a predetermined position facing the peripheral surface of the cylinder. , Two pieces, a long piece and a short piece, which are provided on the peripheral surface of the tubular body and are turned on when the tubular body is rotated and moved to a position facing the switch, and the tubular body is turned on when the power is turned on. Disclosed is a lens movement control device that rotates and restores lens position data lost by previous power-off based on a pulse generated by a pulse generating means at the time of rotation and a change state of a switch on / off signal. .

[0004]

However, in the above lens movement control device, in order to detect the zoom position,
Since a plurality of parts such as a pulse generating means and a switch are provided, a wide space for arranging these parts around the zoom lens is required. In particular, as the weight and size of cameras have been reduced in recent years, the expansion of the space around the zoom lens is contrary to this, and the increase in the number of parts also causes an increase in cost.

Further, since the switch has a structure in which the switch comes into contact with a piece provided on the cylinder and the contact of the switch is pushed up by the piece to turn on, when the switch comes into contact with the piece when the cylinder rotates, the switch is rotated. The resistance of the motor will increase, and the motor may be damaged and damaged. Furthermore, if the interval between both sections is narrowed or the number of sections is increased in order to detect the zoom position quickly, there arises a problem that the switch is caught on the section and the rotation of the cylindrical body is stopped.

In view of the above, it is an object of the present invention to provide a zoom movement control device for detecting the zoom position immediately after power-on with a simple structure.

[0007]

As shown in FIG. 1, the problem-solving means according to the present invention is such that a lens 7 having a plurality of lenses 2 to 5 therein is rotated to move the lenses back and forth to perform zooming and focusing. And a stepping motor 16 for rotating the cylindrical body 7, and the stepping motor 16
Amount detecting means 19 for detecting the amount of rotation of the cylinder 7 by counting drive pulses to the position indicator, and a position indicator having a plurality of magnetically or geometrically different regions formed in the circumferential direction of the cylinder 7. 20 and a non-contact sensor 21 for detecting the position indicator 20, the cylinder 7 is rotated when the power is turned on, and based on the number of pulses by the rotation amount detecting means 19 and the output signal from the non-contact sensor 21. The current zoom position is detected.

Then, according to the content detected by the non-contact sensor 21, the cylindrical body 7 is rotated in a direction not exceeding the rotation range.

Further, the non-contact sensor 21 is an optical sensor, and the position indicator 20 has concave portions A, C, E, G and convex portions B, D, F, H having different lengths in the circumferential direction alternately. And a plurality of sets of the recesses A,
The sum of the circumferential lengths of C, E, G and the convex portions B, D, F, H is the same for each set.

[0010]

In the above means for solving the problems, when the power is turned on, the cylindrical body 7 is rotated, and the rotation amount detecting means 19 counts the drive pulses to the stepping motor 16. Then, the optical sensor 21 which is a non-contact sensor is connected to the position indicator 2
0 geometrically different regions or recesses A, C, E, G
Alternatively, the output signal is changed by detecting any one of the convex portions B, D, F, and H, and which position display body 20 is determined from the number of pulses according to the length at that time.
The current zoom position is detected.

Further, due to the output signal from the optical sensor 21, the cylindrical body 7 does not rotate beyond its rotation range, and the stepping motor is not burdened. Since the sum of the lengths in the circumferential direction of the one set of concave and convex portions A to H of the position display body 20 is the same for each set, the rotational position of the tubular body 7 is located in which of the concave and convex portions A to H. However, the time required to detect the position does not vary greatly, and the position can be detected quickly.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A zoom movement control device according to an embodiment of the present invention is
As shown in FIG. 1, the zoom lens 1 mounted on an optical device such as a camera is used to control zooming (magnification) and focusing, and a lens barrel 6 for holding a plurality of lenses 2 to 5 and the mirror. It is composed of a tubular body 7 rotatably mounted in the barrel 6, a driving means 8 for rotating the tubular body 7 for zooming and focusing, and a control section 9 for controlling the driving means 8.

The lens barrel 6 is fixed to a camera body (not shown) and has a double structure composed of an outer wall 6a and an inner wall 6b. The first lens 2 and the second lens 3 are arranged from the front surface of the lens barrel 6. , The third lens 4 and the fourth lens 5 are arranged in this order. The first lens 2 and the third lens 4 are fixed to the inner wall 6b of the lens barrel 6, and the second lens 3 and the fourth lens 5 are attached to a ring-shaped moving body 10 so that they can be moved back and forth. There is. On the inner wall 6b of the lens barrel 6,
Two guide holes 11 are formed in the front-rear direction, and guide pins 12 projecting from the moving body 10 of the second lens 3 and the fourth lens 5 are inserted into the guide holes 11. The second lens 3 is a variable power lens for changing the magnification, and the fourth lens 5 is a focusing lens for focusing.

The barrel 7 is rotatably mounted between the outer wall 6a and the inner wall 6b of the lens barrel 6, and has a flange 13 formed at the rear end thereof, and a gear with which the driving means 8 described later engages with this flange 13. 14 is formed. Two cam holes 15 are formed obliquely in the cylindrical body 7, and the guide pins 12 of the moving bodies 10 of the second lens 3 and the fourth lens 5 are formed in the cam holes 15 and the guide holes 11 of the lens barrel 6 are formed. To be engaged therethrough.

The driving means 8 is a stepping motor 16
And a drive circuit 17 for driving the stepping motor 16 by issuing a pulse signal, and the pulse from the control unit 9 is given to the stepping motor 16 via the drive circuit 17. The stepping motor 16 has its motor body 16
a is fixed to the outer periphery of the lens barrel 6, and the motor gear 18 attached to the tip of the motor shaft 16b is meshed with the gear 14 formed on the flange 13 of the barrel 7. Then, the rotation of the stepping motor 16 is transmitted to the gear 14 of the tubular body 7 via the motor gear 18, and the tubular body 7 is rotated at the wide end (zoom down) and the tele end as shown in FIG. 1 (b). It stops at (zoom-up), and a mechanical abutting member (not shown) is arranged further in the zoom-down and zoom-up directions than the wide end and the tele end, so that it does not rotate any further.

The control unit 9 is a microcomputer including a CPU, a RAM, a ROM, etc., and judges various photographing conditions based on signals from various switches provided in the camera body or control signals from each unit, According to the result of the determination, the stepping motor 16 is driven to perform zooming, focusing, control of aperture, exposure, etc. to execute the photographing process. Then, the control unit 9 includes a rotation amount detection means 19 that detects the rotation amount of the tubular body 7 when zooming or the like is performed. This rotation amount detecting means 19
Is to count the drive pulses to the stepping motor 16 and detect the amount of rotation of the cylinder 7 from the number of pulses. Based on the amount of rotation of the cylinder 7 by this rotation amount detection means 19, the cylinder 7 The moving distance from the predetermined position (wide end) is determined. When the main switch of the camera is turned off while zooming is performed, the stepping motor 16 is driven to return the cylinder 7 to the wide end. When the main switch is turned on, the cylinder 7 is set to the wide end. You can shoot from the position.

Here, when the power is turned off while the zooming is being performed, except when the main switch is turned off, that is, when the battery is exhausted or the battery is dropped, the cylinder 7 does not return to the wide end and remains stopped at that position. Therefore, the control unit 9 loses this zoom position information, and even if the batteries are replaced or reattached, the previous zoom position cannot be known.
Therefore, the lens movement control device of the present embodiment is provided with a position display body 20 that indicates the rotational position of the cylindrical body 7 and a non-contact sensor 21 that detects the position display body 20, and the control unit 9
When the battery is installed and the power is turned on with the zoom position information disappeared, the cylinder 7 is rotated to rotate the rotation amount detecting means 19
There is provided a zoom position recognizing means 22 for detecting the current zoom position based on the rotation amount of the cylinder 7 and the output signal from the non-contact sensor 21.

As shown in FIGS. 1 and 2, the position indicating body 20 has regions that are geometrically different in the circumferential direction of the cylindrical body 7, that is, uneven portions A to H having different lengths are alternately formed in a fan shape. The cylindrical body 7 is radially protruded at a position opposite to the gear 14 at the rear end with respect to the flange 13 of the cylindrical body 7 and sandwiching the shaft center, and is arranged within the range of the wide end and the tele end. Position indicator 2
0 is a concave portion A, a convex portion B, from the wide end side to the tele end,
The concave portion C, the convex portion D, the concave portion E, the convex portion F, the concave portion G, and the convex portion H are arranged in this order, and the concave-convex portions A to H have the maximum lengths of the concave portion A and the convex portion H. Hereinafter, the concave portion C and the convex portion F, the concave portion E and the convex portion D, and the concave portion G and the convex portion B are set to be shorter in this order. In addition, the sum of the lengths in the circumferential direction of a pair of concavo-convex portions A to H that are adjacent to each other is the same, that is, the concave portion A + the convex portion B = the concave portion C + the convex portion D = the concave portion E + the convex portion F = the concave portion G +. It is a convex portion H.

In addition, the uneven portions A to
The number of pulses of the stepping motor 16 that rotates the length of H is as follows: concave portion A = a, convex portion B = b, concave portion C =
c, convex D = d, concave E = e, convex F = f, concave G =
g and the convex portion H = h, these data are
Is stored in the control unit 9 in advance as the data of the rotation amount. The relationship between the numbers of pulses is a>c>e> g, h
>F>d> b, a + b = c + d = e + f = g + h.

The non-contact sensor 21 is a photo interrupter which is an optical sensor for detecting the concave and convex portions A to H of the position display body 20 and outputting a low or high signal, and as shown in FIGS. In the lower part of the lens barrel 6 facing the gear 14 of the stepping motor 16 with the axis center sandwiched so that the position indicator 20 is located in the passage 28 formed in the center of the concave holder 27 in which the light receiving element 26 is installed. Installed. The photo interrupter 21 is a light emitting / receiving element 2
5, 26 are arranged opposite to each other with the passageway 28 in between, and an optical path from the light emitting element 25 to the light receiving element 26 via the passageway 28 is formed, and the optical path is formed by the convex portions B, D, F, H of the position indicator 20. Is cut off and a high signal is output, and the recesses A, C,
The optical paths are opened by E and G and a low signal is output.

Then, the zoom position recognizing means 22 is turned on by mounting a battery, and the photo interrupter 2 is turned on.
In accordance with the output signal from 1, when the output signal of the photo interrupter 21 is low, the barrel 7 is moved to the tele end side, and when it is high, the barrel 7 is moved to the wide end side. And the function to rotate the cylindrical body 7 and the output signal of the photo interrupter 21 is first changed from low to high by rotating the cylinder 7.
Alternatively, the function of starting the counting of the driving pulse to the stepping motor 16 by the rotation amount detecting means 19 from the time of switching from the high level to the low level and the function of the photo interrupter 21 after the counting of the driving pulse to the stepping motor 16 are started. It has a function of stopping the rotation of the stepping motor 16 when the output signal changes from low to high or from high to low, and recognizing the current zoom position from the number of pulses counted at this time. 2 is rotated to the tele end side, if the number of pulses is b, the position of L shown in FIG. 2, if the number of pulses is d, the position of N, if the number of pulses is f, the position of P, the number of pulses is If it is h, it is recognized as the R (tele end) position, while if the number of pulses is g when the cylinder 7 is rotated to the wide end side, the position is P,
If the number of pulses is e, the position is N, if the number of pulses is c, the position is L, and if the number of pulses is a, the position is J (wide end).

Next, the operation of detecting the current zoom position from the state in which the zoom position has disappeared due to battery exhaustion or the like will be described with reference to the flowchart of FIG. When the battery is installed and the power is turned on, the control unit 9 first receives the output signal from the photo interrupter 21 and detects the concave portions A, C, E, G or the convex portions B, D, F, H of the cylindrical body 7. It is detected which one of them is at the position of the photo interrupter 21.
At this time, if the photo interrupter 21 outputs a low signal, the control unit 9 causes the recesses A, C, E, G of the position display body 20 to be detected.
Is determined to be at the position of the photo interrupter 21, and a drive pulse for rotating the tubular body 7 to the tele end side is applied to the stepping motor 16 via the drive circuit 17 to rotate the stepping motor 16 to the tele end side.

After that, when the output signal of the photo interrupter 21 changes from low to high, the control section 9 starts counting drive pulses to the stepping motor 16. At this time, when the high-to-low inversion of the output signal of the photo interrupter 21 is detected at the same time as the number of pulses to be counted reaches f or before it reaches f, the driving of the stepping motor 16 is stopped and the cylindrical body 7 is rotated. And the counting of the number of pulses is stopped. If the counted number of pulses is b, it is recognized that the current zoom position is zoomed in at a position of L, that is, the zoom-in is performed by the concave portion A + the convex portion B from the wide end. If the number of pulses is d, the position is N, and if the number of pulses is f, the zoom position is P. However, if the output signal of the photo interrupter 21 does not change from high to low even if the number of drive pulses is started and the number of pulses exceeds f,
It is determined that the zoom position is the convex portion H, the driving of the stepping motor 16 is stopped at the same time when the number of pulses reaches h, and it is recognized as the position of R which is the tele end.

On the other hand, if the output signal of the photo interrupter 21 is high when the power is turned on, it is determined that the convex portions B, D, F, H of the position indicator 20 are at the position of the photo interrupter 21, and the cylindrical body is determined. Rotate 7 toward the wide end. After that, by inverting the output signal of the photo interrupter 21 from high to low, counting of drive pulses to the stepping motor 16 is started, and at the same time when the number of pulses reaches c,
Alternatively, when the inversion of the output signal of the photo interrupter 21 from low to high is detected before reaching c, the rotation of the cylindrical body 7 is stopped and the counting of the number of pulses is stopped. If the counted number of pulses is g, the current zoom position is the position P, if the number of pulses is e, the position is N, and if the number of pulses is c, the zoom position is recognized as the position L. If the output signal of the photo interrupter 21 does not invert from low to high even after the number of pulses exceeds c after the start of counting the driving pulse, it is determined that the zoom position is the concave portion A, and the number of pulses is a. At the same time, the driving of the stepping motor 16 is stopped and it is recognized that the position is J, which is the wide end. Then, after that, the rotation amount detecting means 19 counts the drive pulses of the stepping motor 16 to recognize the normal zoom position, and is used as a parameter for zooming or focusing.

The stepping motor 1 after the power is turned on
If the driving pulse from the driving start to the stop of 6 is separately counted and the stepping motor 16 is driven in the reverse direction by the number of pulses separately counted after the zoom position is recognized, the power is restored to the zoom position where the power is cut off. be able to.

In this way, the cylindrical body 7 is rotated, and the boundary between the concave and convex portions A to H of the position indicator 20 is moved to the photo interrupter 21.
The current zoom position can be detected by counting the drive pulses to the stepping motor 16 up to the boundary.

Moreover, the set of concave and convex portions A of the position indicator 20
The zoom position can be detected only by rotating between .about.H and the maximum pulse number when the concave portion A or the convex portion B is located at the position of the photo interrupter 21 is a + b, and when the concave portion C or the convex portion D is c + d, the concave portion E. Alternatively, the convex portion F is e + f, and the concave portion G or the convex portion H is g + h, and the sum of the circumferential lengths of the concave and convex portions A to H is the same (a + b = c + d =).
Since e + f = g + h), it is possible to reduce the variation in the time until the zoom position is recognized, that is, the time corresponding to the maximum movement of one section, regardless of the position of the cylindrical body 7. Therefore, even when the power is turned off and the zoom position information is lost due to battery exhaustion or the like, if the power is turned on, the current zoom position can be recognized quickly and in a short time.

Since the photo interrupter 21 detects the uneven portions A to H of the position display body 20, the uneven portion A is detected.
.. H and the photo interrupter 21 do not come into contact with each other, the rotation of the cylindrical body 7 is not adversely affected or caught due to friction or the like, and the stepping motor 16 or the like is not burdened. Therefore, the life of each component is extended, the frequency of maintenance such as replacement is reduced, and the reliability of the camera is improved.

Further, since the stepping motor 16 and the photo interrupter 21 are used, there is no need for a pulse generating means or the like as in the conventional case, the space for arranging parts can be reduced, and the weight and size can be reduced.

Further, both ends of the position display body 20 are arranged so as to have a concave portion A on the wide end side and a convex portion H on the tele end side, respectively, and when the concave portions A, C, E and G are detected when the power is turned on, the cylindrical body 7 To the tele end side, and when the convex portions B, D, F, and H are detected, the cylinder body 7 is rotated to the wide end side, so that the cylinder body 7 does not rotate beyond the wide end or the tele end, and is rotated. The stepping motor 16 will not be overloaded without colliding with an abutting member that stops the stepping motor.

The present invention is not limited to the above embodiment, and it goes without saying that many modifications and changes can be made to the above embodiment within the scope of the present invention. For example, in the above-described embodiment, the uneven portions A to H of the position indicator 20 are provided at four places, respectively. However, if each length is shortened to five places, or six places, or more, The initial value of the zoom position can be detected even faster.

Further, although the unevenness is formed on the plate-shaped member as the position display body 20, it may have a corrugated shape or other geometric shapes, and may have a three-dimensionally uneven shape or a magnetically different shape.

Further, the photo interrupter 21, which is an optical sensor, is used as the non-contact sensor.
A distance sensor or other non-contact type sensor may be used.

In the above embodiment, the zoom lens 1 of the camera has been described, but the zoom lens 1 of the camera can also be used for an optical device mounted on a microscope, a video movie machine or a copying machine.

[0035]

As is apparent from the above description, according to the present invention, the cylinder is rotated when the power is turned on, the position indicator is detected by the non-contact sensor, and the stepping motor is driven until the position indicator is detected. The current value of the zoom position can be detected by counting the pulses.

Moreover, the zoom position can be detected simply by rotating between the pair of concave and convex portions of the position indicating body, and the sum of the circumferential lengths of the concave and convex portions is the same, so that the cylindrical body is Even at the position, the position can be detected if there is a time for moving a maximum of one section, and the variation in the time can be suppressed to be small. Therefore, even if the power is turned off and the current zoom position cannot be known due to battery exhaustion or the like, if the power is turned on, the current zoom position can be recognized quickly and in a short time.

Since the position display body is detected by the non-contact sensor such as an optical sensor, the position display body and the non-contact sensor do not come into contact with each other, so that the rotation of the cylinder is adversely affected or caught due to friction or the like. There is no need to do so, and no burden is placed on the stepping motor or the like. Therefore, the life of each part is extended and the frequency of maintenance such as replacement is reduced,
The reliability of the device is improved.

Further, since a stepping motor and an optical sensor are used, there is no need for a pulse generating means or the like as in the conventional case, a space for arranging parts can be reduced, and a microscope or a camera can be made lightweight and compact. become.

Further, the output signal from the non-contact sensor causes the cylinder to rotate in a direction that does not exceed the rotation range, that is, the cylinder does not rotate beyond the rotation range, so that the stepping motor and the drive transmission system are excessively large. Does not impose a heavy burden.

[Brief description of drawings]

1A and 1B show a zoom movement control device according to an embodiment of the present invention, wherein FIG. 1A is an overall configuration diagram and FIG. 1B is a front view.

FIG. 2 is a front view of the position indicator.

FIG. 3 is a block diagram of a photo interrupter.

FIG. 4 is a flowchart showing a control operation for detecting the current zoom position when the power is off.

[Explanation of symbols]

 2-5 Lenses 7 Cylindrical body 16 Stepping motor 19 Rotation amount detecting means 20 Position display body 21 Photo interrupters A, C, E, G Recesses B, D, F, H Convex parts

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location G03B 13/34

Claims (3)

[Claims] 1. A stepping motor for rotating the cylinder, which is configured to move the lens back and forth for zooming and focusing by rotating a cylinder containing a plurality of lenses. Amount detecting means for detecting the amount of rotation of the cylinder by counting drive pulses to the position indicator, and a position indicator having a plurality of magnetically or geometrically different regions formed in the circumferential direction of the cylinder. A non-contact sensor for detecting the position indicator, the cylinder is rotated when the power is turned on, and the current zoom position is determined based on the number of pulses by the rotation amount detection means and the output signal from the non-contact sensor. A zoom movement control device characterized by detecting the. 2. The zoom movement control device according to claim 1, wherein the cylinder is rotated in a direction not exceeding a rotation range according to the detection content of the non-contact sensor. 3. The non-contact sensor is an optical sensor, and the position indicator has a plurality of sets of recesses and protrusions having different lengths in the circumferential direction, which are alternately formed. 3. The zoom movement control device according to claim 1, wherein the sum of the circumferential lengths of the parts is the same for each set.