JP4408673B2 - Imaging device with variable magnification function - Google Patents

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an imaging apparatus with a magnification function that performs a magnification operation, such as a digital camera, and more particularly to an imaging apparatus with a magnification function that can reliably recover a positional shift caused by an abnormal operation.

In general, in a focal length detection device of a zoom photographing optical system in a camera or the like, the amount and direction of rotation of a cam ring that changes the focal length of the photographing optical system by rotating around the optical axis of the photographing optical system. A zoom encoder is used to detect.
Then, a conventional absolute value encoder is made non-contact, and the position detection means is changed to a predetermined value according to the output of the position detection means at least near the wide-angle end and near the telephoto end.
That is, as a prior art, Japanese Patent Laid-Open No. 05-181050 (detecting a rotation amount and a rotation direction of a cam ring that changes a focal length of a photographing optical system by rotating around an optical axis of the photographing optical system) In the zoom encoder, non-contact type pulse generating means for generating a pulse signal in accordance with the rotation of the cam ring, which is the driving means 1 for changing the focal length of the photographing optical system, and the above in accordance with the rotation direction of the cam ring. Counting means for adding or subtracting a pulse signal, position detecting means for detecting a predetermined position signal at least near the wide-angle end and the telephoto end of the focal length, and the counting means according to a change in the output of the position detecting means A count value changing means for changing the count value to a predetermined value, and zoom information for obtaining zoom information by an output from the counting means. Equipped with a detection means), and the like.
JP 05-181050 A

However, the conventional imaging device with a zoom function has the following problems.
In the retractable lens barrel of the conventional imaging device with a zooming function, the feeding accuracy is necessary to prevent out-of-focus, but the lens barrel may be touched or pressed by hand because it is fed out. . In such a case, the zoom position is shifted in a lens barrel that has not been subjected to absolute position detection, resulting in out of focus.
Here, in order to detect the absolute position of the zoom, a method using a resistor plate is known, but it is expensive, and the resistor plate and the contact piece are scraped due to durability, so that the reliability is inferior. There is a problem that a new problem occurs due to the worn powder.
Further, as an abnormal operation, there is a state in which the lens barrel is pressed by hand during the zoom operation.
In this case, the motor is driven, but the lens barrel cannot move. At that time, the pulse generating means existing in the driving means may be reversed. In that case, if there is a means for detecting reverse rotation, there is no problem if the addition / subtraction operation is performed in consideration of the reverse rotation count number. However, in order to detect the reverse rotation, one photo interrupter (counting means) is added and 2 It is necessary to detect inversion from one phase or use a two-phase photo interrupter. Therefore, there is a problem that detecting the reverse rotation involves an increase in cost and an increase in the size of the apparatus.

Another method is to correct miscounted counts.
This divides the working angle of the zoom lens and the working angle of the rotary cam that moves the zoom lens by a plurality of predetermined position detecting means, and corrects each time it passes through each of the predetermined position detecting means, This is a method for preventing cumulative miscounting.
Since this method requires a plurality of predetermined position detection means, the apparatus is increased in size and cost, and the control is complicated.
An example thereof is shown in FIG. 13 of Japanese Patent Laid-Open No. 05-181050. As shown in the figure, two photo reflectors are used for PR1 and PR2.
Further, as shown in FIG. 3 of Japanese Patent Laid-Open No. 05-181050, when three or more areas are divided by one predetermined position detecting means, the power source is removed at the γ position and the power source is turned on again. A big problem arises that it is impossible to determine whether it exists in the area A or in the area C.
That is, when the initialization operation is performed, it is originally in the γ position (C area), so it must be driven in the B area direction. However, if it is determined that the camera recognition exists in the A area, it is driven in the B area direction. End up. In that case, since it is driven further in the TELE direction from the γ position, it is driven out of the operating area, which may cause a failure.
2 and 12 of Japanese Patent Laid-Open No. 05-181050, when the lens barrel is pushed by hand, the force may reverse the driving means via the moving means. In brief, pressing the lens barrel causes the lens barrel to retract. In this case, the absolute position of the lens barrel is shifted, causing a focus shift.
It is an object of the present invention to perform miscount correction without complicating the control software, lengthening the start-up time and zooming time, and reducing misalignment due to abnormal operation. It is an object to provide an image pickup apparatus with a zooming function that can reliably recover image data.

In order to achieve the above-mentioned object, the invention described in claim 1 includes a variable magnification optical system having a variable magnification function, and a rotating ring that drives the variable magnification optical system within a use range of a storage-wide-angle end-telephoto end. Driving means for supplying rotational power to the rotating ring; pulse generating means for generating a pulse signal in accordance with the amount of rotation of the rotating ring ; and a signal indicating the predetermined position by detecting a predetermined position of the rotating ring. a single predetermined position detecting means for outputting, an image pickup apparatus having a counting means for counting the pulses generated in the pulse generating means movement, until the wide angle end toward the wide-angle the variable magnification optical system from the housing A count value correcting means for correcting the count value of the counting means based on a signal indicating the predetermined position output from the predetermined position detecting means , and the predetermined position is a wide angle of the variable magnification optical system. End Characterized in that it is arranged be shifted in the housing side.
According to a second aspect of the present invention, in the imaging apparatus with a scaling function according to the first aspect , the driving unit is configured to dispose a gear train from a motor and engage the moving unit, and the first stage of the gear train is It consists of a worm gear.
According to a third aspect of the present invention, in the imaging apparatus with a scaling function according to the first or second aspect , the driving unit is configured to dispose a gear train from a motor and engage the moving unit. The first stage consists of a pulley and a belt.

According to the first aspect of the present invention, when the camera is set to the zoom position at the wide-angle end (storage-wide-angle end), a pulse erroneously counted from the pulse generating means in an abnormal operation such as pressing the lens barrel by hand is generated. Even if it occurs, because the predetermined position is located at the closest position to the wide-angle end on the storage side, the influence of the erroneous count can be minimized, and the lens barrel can be pressed by hand in the same way when zooming. Even when an erroneously counted pulse is generated from the pulse generating means in an abnormal operation, a good focusing can be maintained without accumulating the generated erroneous count by performing a zooming operation that passes through the wide-angle end. .
Further, there is no influence on the zooming time from the wide-angle end to the telephoto end, which is usually anxious, and the influence can be suppressed in a short time at the telephoto end-wide-angle end.
Further, this configuration eliminates the need for pulse generation means and erroneous count detection means (usually adding one photointerrupter or using a two-phase photointerrupter: a two-phase photointerrupter is expensive). Error count correction can be performed at low cost and in a small space.
According to the second aspect of the present invention, the first stage of the gear train is a worm gear, so that the lens barrel does not retract even when the lens barrel is pushed, and more accurate against external pressure (abnormal operation) is secured. It becomes possible.
According to the invention of claim 3, since the first stage of the gear train is a pulley and a belt, the transmission efficiency is improved as compared with the worm gear, so that the gear reduction ratio can be reduced and the zooming time is high. In addition, the generation of sound can be suppressed, and the reverse rotation of the motor can be prevented as compared with a normal spur gear, so that it is resistant to abnormal operation and can provide a quiet and high speed zoom mechanism.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a functional block diagram of an embodiment of a zoom mechanism that is a main part of an imaging apparatus with a zoom function according to the present invention.
As shown in FIG. 1, the zooming mechanism of this imaging apparatus includes a zooming optical system 1 having a zooming function, a rotary ring (moving means) 3 for driving the zooming optical system 1, and a rotary ring . and drive means 5 for supplying rotational power, a pulse generating means 7 for generating a pulse signal in response to the rotation amount of the rotating ring, and detecting a predetermined position of the rotary ring, and outputs a signal indicating a predetermined position single the position detecting means 9, the counting means 11 for counting the pulses generated in the pulse generating means 7, when moving the variable power optical system from the storage to the wide-angle end toward the wide-angle, position detecting means 9 the count value correcting means 13 for correcting the count value of the counting means 11 based on a signal indicating a predetermined position to be output, the zoom information detection for detecting a zoom information based on the count pulse by the counting means 11 And means 15, and a shift correction means 17 for correcting the amount of movement by the moving means 3 on the basis of the detected said zoom information.
The predetermined position is shifted from the wide-angle end of the variable magnification optical system 1 toward the storage side.

FIG. 2 is a configuration perspective view of the zoom mechanism of the imaging apparatus shown in FIG.
As shown in FIG. 2, a zoom encoder 21 is provided on a rotary ring 20 that rotates in a direction indicated by reference symbol A or A to drive a zoom lens. As shown in FIG. 3, the zoom encoder 21 includes three parts, a retracted part A, an imaging range part B, and a region C beyond the telephoto end position. Of these, the A part and the C part are silver or high in reflectance. White and the B part is black with low reflectivity.
The output signal of the zoom photo reflector 23 (ZPR) fixed at a predetermined position in the camera body is changed by the rotation of the zoom encoder 21. That is, when the photoreflector 23 faces the position α shown in FIG. 3, it is in the retracted state, and when the photoreflector 23 faces the position β, it is in the wide state and faces the position γ. When it is in the tele state.

The zoom drive unit 25 is provided on a zoom motor 27, a reduction gear train 29, an axial extension of the zoom motor 27, a slit 31 that rotates in conjunction with the zoom motor 27, and in the vicinity of the slit 31. A zoom photo interrupter 33 (ZPI) that is arranged and generates an output signal in response to the rotation of the slit 31 and a drive gear provided on the outer periphery of the rotary ring 20 are meshed with the final gear of the reduction gear train 29. And an output gear 37 that meshes with the zoom motor 27 and transmits the rotational force of the zoom motor 27 to the rotary ring 20.
The output ends of the photo reflector 23 and the photo interrupter 33 are a CPU including the pulse generating means 7, the counting means 11, the count value correcting means 13, the zoom information detecting means 15, and the movement correcting means 17, etc. The CPU detects the current focal length based on the output signals of the photo reflector 23 and the photo interrupter 33, and corrects the movement.
The spacing ring 20 constitutes the moving means 3, the zoom motor 27 , the reduction gear train 29, the drive gear 35, and the output gear 37 constitute the drive means 5 , and the photo reflector 23 and the photo interrupter 33 are The predetermined position detecting means 9 is configured.
The feature of the present invention is that when the predetermined position detecting means 9 moves from the telephoto side to the wide angle side in the backlash removing operation performed during the zooming operation, the zooming optical system is stored in the storage-wide-angle end-telephoto end. The predetermined position of the zoom is detected at a position closest to the wide-angle end on the storage side in the use range. First, the storage side of the storage-wide-angle end-tele end of the zoom optical system is first described below. The operation of detecting the predetermined zoom position at the closest position at the wide-angle end will be described with reference to a conventional example.

FIG. 4 is a diagram showing the relationship between the detection state of the conventional predetermined position detecting means and the variable magnification optical system.
As shown in FIG. 4, the switching of the position detection signal for detecting the predetermined zoom position by the predetermined position detecting means is set immediately before the optical variable magnification lens is housed.
Here, there are a first group, a second group, and a third group as variable power lenses of the optical system, and the third group performs focus adjustment. In addition, the first group and the second group can be moved simultaneously by one moving means, and the third group is configured independently for performing focus adjustment.
FIG. 5 is a diagram showing the relationship between the detection state of the predetermined position detecting means 9 according to the present invention and the variable magnification optical system.
As shown in FIG. 5, the switching of the position detection signal for detecting the predetermined zoom position by the predetermined position detecting means is set to be close to the wide-angle end on the storage side, becomes low on the storage side from the switching point, and the telephoto On the side, it is High.
In other words, by limiting to a single unit, the driving direction for detecting the switching point can be known when the power is turned on the next time, regardless of the power supply in any state.

FIG. 6 is a diagram illustrating a count state in the conventional activation and scaling operation.
As shown in FIG. 6, first, the zoom lens in the housed state is set at the wide-angle end by the activation operation. When the position detection signal is switched a little from the storage, the switching of the position detection signal is detected, count correction is performed based on the detected signal, and a predetermined count number is set at the wide angle end.
At this time, if the feeding of the rotating ring 20 is hindered in the intermediate area from the storage to the wide-angle end, the count is erroneously counted at that point. That is, since the switching of the position detection signal has already passed, the subsequent erroneous count is accumulated as it is.
Next, zooming operation from the wide-angle end to the telephoto side is performed, but backlash removal is performed only when moving from the telephoto side to the wide-angle side. Therefore, a predetermined amount of movement is moved to the telephoto side to complete, but if an erroneous count occurs at this time, the erroneous count is further accumulated.
Next, the zooming operation from the telephoto side to the wide angle side is performed by moving a predetermined feed amount to the wide angle side, and then performing backlash removal, further moving to the wide angle end, and performing backlash removal. Completed. In other words, the erroneous count generated during zooming is further accumulated by zooming operation including backlash removal from the telephoto side to the wide-angle end.
FIG. 7 is a flowchart of a zooming operation including backlash removal from the telephoto side to the wide-angle end. As shown in FIG. 7, when a movement signal in the wide-angle direction is detected (S1), the position is set to the wide-angle end position (S2), and then backlash-removing operation is performed (S3). Is completed (S4).

FIG. 8 is a diagram showing a count state in the start-up and scaling operation according to the present invention.
As shown in FIG. 8, first, the lens in the retracted state is set at the wide-angle end upon activation, but the switching of the position detection signal is detected near the wide-angle end, and the detected signal is used as a reference. A predetermined count number is fed out and set at the wide angle end.
Here, even when the feeding of the rotary ring 20 is hindered in the intermediate region from the storage to the wide angle end, the position detection signal is switched near the wide angle end, so that it is hardly affected by the erroneous count.
Next, the zooming operation from the wide-angle end to the telephoto side is performed. Similarly, backlash removal is performed only when moving from the telephoto side to the wide-angle side. Therefore, a predetermined amount of movement is moved to the telephoto side to complete. Similarly, if an erroneous count occurs at this time, it will be accumulated.
Next, zooming operation from the telephoto side to the wide-angle side is performed. After moving the specified feed amount to the wide-angle side, the backlash is removed and then moved to the wide-angle end to complete the backlash removal. To do. Here, when moving to the wide-angle end, switching of the position detection signal is detected during backlash removal, and a predetermined count is fed out and set at the wide-angle end. That is, it can be seen that an erroneous count that occurs during zooming is reset by zooming from the telephoto side to the wide-angle end.
FIG. 9 is a flowchart of the zooming operation including backlash removal from the telephoto side to the wide-angle end according to the present invention. As shown in FIG. 9, when a movement signal in the wide-angle direction is detected (S1), it is set at the wide-angle end position (S2), and then a backlash removing operation is performed (S3). Next, in the backlash removing operation, it is determined whether or not the zoom position detection signal is low (S5). If the zoom position detection signal is low, count correction is performed (S6) and the position to the wide-angle end position is corrected. The setting is completed (S7). If the zoom position detection signal is not low, the zoom position detection signal is moved in the storage direction until the zoom position detection signal becomes low (S8). In this way, by making only the backlash removal amount at the wide-angle end larger than the normal backlash removal amount, the predetermined position detection position varies more toward the storage side, and the predetermined position detection can be performed with the normal backlash removal amount. In the case where there is not, it is possible to reliably detect the predetermined position by increasing only the backlash removal amount at the wide-angle end, and it is possible to minimize the increase in zooming time due to the increase in the backlash removal amount in the normal region.
In the above embodiment, the first stage of the reduction gear train 29 of the zoom drive unit 25 is used as the worm gear 41 as shown in FIG. 10, or the first stage of the reduction gear train 29 of the zoom drive unit 25 is used as shown in FIG. A pulley 43 and a belt 45 can also be used.

As shown in FIG. 10, the first stage of the reduction gear train 29 of the zoom drive unit 25 is the worm gear 41, so that the lens barrel is not retracted even when the lens barrel is pushed, so that the external pressure (abnormal operation) can be prevented. It is possible to ensure accuracy.
That is, as a problem that occurs in abnormal operations such as pressing the lens barrel by hand, when the above-mentioned erroneous count occurs and the lens barrel is pressed with a stronger force, the force is driven through the moving means. There is a case where the means is reversed (the lens barrel is retracted when the lens barrel is pushed in a simple explanation). In this case, the absolute position of the lens barrel is shifted, and a focus shift occurs. Is solved by using the worm gear 41.
More specifically, the force pushing the lens barrel tries to reversely rotate the gear train as the driving means. However, since the worm gear 41 is converted into a right angle, the worm gear 41 can reversely rotate. Since the lens barrel is not pushed, it will not retract.
In addition, in the case of the worm gear 41, it is known that generation of sound is suppressed in addition to the above advantages. However, it is known that the transmission efficiency is poor and a large gear reduction ratio is required, so that it is not suitable for increasing the zooming time.
As shown in FIG. 11, by using the first stage of the reduction gear train 29 of the zoom drive unit 25 as the pulley 43 and the belt 45, the transmission efficiency is improved as compared with the worm gear 41, so the gear reduction ratio can be reduced. The speed of zooming can be increased, the generation of sound can be suppressed, and the reverse rotation of the motor can be prevented compared to a normal spur gear. can do.
FIG. 12 shows the evaluation of loss in various configurations of the first stage of the reduction gear train 29 of the zoom drive unit 25 described above.

FIG. 3 is a functional block diagram of an embodiment of a zoom mechanism that is a main part of an imaging apparatus with a zoom function according to the present invention. FIG. 2 is a configuration perspective view of a zoom mechanism of the image pickup apparatus illustrated in FIG. 1. 3 is a time chart showing a relationship between a reading pattern of the photo reflector 23 shown in FIG. 2 and an output of the photo reflector 23. FIG. It is a figure which shows the relationship between the detection state of the conventional predetermined position detection means, and a variable magnification optical system. It is a figure which shows the relationship between the detection state of the predetermined position detection means 9 by this invention, and a variable magnification optical system. It is a figure which shows the condition of the count in the conventional starting and scaling operation. It is a flowchart of a zooming operation including backlash removal from the conventional telephoto side to the wide-angle end. It is a figure which shows the condition of the count in the starting and scaling operation by this invention. 6 is a flowchart of a zooming operation including backlash removal from the telephoto side to the wide-angle end according to the present invention. FIG. 10 is a perspective view of a modification in which the first stage of the reduction gear train 29 of the zoom drive unit 25 shown in FIG. 2 is a worm gear. FIG. 10 is a perspective view of a modification in which the first stage of the reduction gear train 29 of the zoom drive unit 25 shown in FIG. 2 is a pulley and a belt. FIG. 6 is a diagram illustrating evaluation of loss in various configurations of the first stage of a reduction gear train 29 of the zoom drive unit 25.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Variable magnification optical system, 3 ... Moving means, 5 ... Drive means, 7 ... Pulse generation means, 9 ... Predetermined position detection means, 11 ... Count means, 13 ... Count value correction means, 15 ... Zoom information detection means, 17 DESCRIPTION OF SYMBOLS ... Movement correction means, 20 ... Rotating ring, 21 ... Zoom encoder, 23 ... Zoom photo reflector, 25 ... Zoom drive unit, 27 ... Zoom motor, 29 ... Reduction gear train, 31 ... Slit, 33 ... Zoom photo interrupter, 35 ... Drive gear, 37 ... output gear, 41 ... worm gear, 43 ... pulley, 45 ... belt

Claims (3)

A zooming optical system having a zooming function, a rotating ring that drives the zooming optical system within a use range of a wide-angle end and a telephoto end, a driving unit that supplies rotational power to the rotating ring, and the rotating ring Generated in the pulse generating means, a pulse generating means for generating a pulse signal in accordance with the amount of rotation, a single predetermined position detecting means for detecting a predetermined position of the rotating ring and outputting a signal indicating the predetermined position, and the pulse generating means An image pickup apparatus for counting the number of pulses, and indicating the predetermined position output by the predetermined position detection means when the variable magnification optical system moves from the storage to the wide-angle end toward the wide-angle end. It has a count value correction means for correcting the count value of said counting means on the basis of the signal, varying said predetermined position, characterized in that it is arranged offset in the housing side than the wide angle end of the zoom lens system and Double Ability with the imaging device. Said drive means is configured to engage the moving means arranged gear train from the motor, the first stage zooming function imaging apparatus according to claim 1, comprising the worm gear of the gear train. Said drive means is configured to engage the moving means arranged gear train from the motor, with zooming function according to claim 1 or 2 wherein the first stage of the gear train is characterized in that it consists of a pulley and a belt Imaging device.

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