JP2012103394A - Optical apparatus and control method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical apparatus capable of acquiring a driving correction amount for correcting a driving amount of a focus lens accurately and easily, and provide a control method thereof.SOLUTION: An optical apparatus comprises: a photo interrupter 14 that detects an origin of a focus lens 11a and includes an output change region R where output changes continuously; and a camera CPU that wobbles the focus lens from a position P2 in the output change region, repeats wobbling while updating a driving correction amount Y for correcting a driving amount X which is provided to a stepping motor 10 so that output values V4 to V6 of the photo interrupter corresponding to positions P4 to P6 of the focus lens which fall under end parts of reciprocatory drive on the position P1 side come close to an output value V2 of the photo interrupter corresponding to the position 2 in the wobbling, and that uses the driving correction amount Y proximate to the output value V2 for focus adjustment.

Description

  The present invention relates to an optical apparatus (for example, an interchangeable lens or a digital camera) having a focus lens for performing focus adjustment, and a control method thereof.

  In optical equipment, the amount of drive (number of drive pulses, etc.) input to the motor to move the focus lens due to mechanical backlash, inertial force, temperature change, change over time, and the actual amount of focus lens movement May be different. Therefore, in this case, it is necessary to acquire a drive correction amount (such as the number of drive pulses) and correct the drive amount with the drive correction amount.

  Therefore, in Patent Document 1, the focus lens is driven by a predetermined drive amount from the discontinuous point of the output of the linear encoder that detects the position of the focus lens, and then reversely driven until the discontinuous point is detected. The difference in the number of drive pulses at that time is stored as a backlash amount.

JP 2007-178762 A

  However, since Patent Document 1 uses a new position detection means called a linear encoder, the optical apparatus becomes large. Further, since the output change of the linear encoder is 0 to 1 or 1 to 0, it is discontinuous, and the position of the focus lens during the discontinuous change cannot be accurately grasped. As a result, the drive correction amount for correcting the drive amount of the focus lens cannot be obtained accurately, leading to a decrease in focus adjustment (AF) accuracy.

  Accordingly, an object of the present invention is to provide an optical apparatus and a control method therefor capable of obtaining a drive correction amount for correcting the drive amount of the focus lens accurately and easily.

An optical apparatus of the present invention is an optical apparatus that performs focus adjustment by wobbling a focus lens that constitutes a photographing optical system that forms an optical image in the optical axis direction of the photographing optical system,
A motor for driving the focus lens; detection means for detecting an origin when driving the focus lens and having an output change region in which an output continuously changes; and the focus lens in the output change region The second position of the focus lens, which is the end of reciprocating drive on the first position side, is moved to the first output value of the detection means corresponding to the first position of the focus lens. The wobbling is repeated while updating the drive correction amount for correcting the drive amount applied to the motor so that the second output value of the detection means corresponding to the second approach value approaches, and the second output value becomes the first output value. Control means for holding the drive correction amount when it is closest, and using the held drive correction amount for the focus adjustment. That.

  According to the present invention, it is possible to provide an optical apparatus capable of acquiring a drive correction amount for correcting the drive amount of the focus lens accurately and easily and a control method thereof.

It is a block diagram of a single-lens reflex digital camera. Example 1 6 is a flowchart for explaining the TV-AF operation of the single-lens reflex digital camera shown in FIG. 1. Example 1 It is a figure which shows the relationship between the position of the focus lens of the single-lens reflex digital camera shown in FIG. 1, and the output of a photo interrupter. Example 1 It is a flowchart of the method of test | inspecting the moving amount | distance of the focus lens shown in FIG. Example 1 5 is a graph showing an example of the relationship between the position of a focus lens and the output of a photo interrupter in the inspection method of FIG. 5 is a detailed flowchart of S209 in FIG. 4. Example 1 5 is a detailed flowchart of S210 of FIG. Example 1 It is a block diagram of a single-lens reflex digital camera. (Example 2) It is a flowchart of the method of test | inspecting the moving amount | distance of the focus lens shown in FIG. (Example 2)

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a block diagram of a single-lens reflex digital camera 1A according to the first embodiment. The single-lens reflex digital camera 1 </ b> A is configured such that an interchangeable lens (lens barrel) 2 </ b> A is detachable from the camera body 3. The interchangeable lens 2A or the single-lens reflex digital camera 1 as the camera body 3 to which the interchangeable lens 2A is attached functions as an optical device of this embodiment. Of course, the interchangeable lens 2A may be integral with the camera body 3.

  A camera CPU (control means) 4, a control system power supply 5, a drive system power supply 6, a communication unit 7, a lens mounting detection unit 8, and the like are provided in the camera body 3. The camera CPU 4 controls the operation of the entire camera and is composed of a microcomputer. The control system power supply 5 supplies power to a control system circuit that requires a stable output voltage with a relatively small amount of power consumption such as a photometry unit and a focus adjustment unit (not shown). The drive system power supply 6 detects the voltage and power of the control system power supply 5 and supplies power to a drive system circuit with relatively large power consumption, such as the interchangeable lens 2A and a shutter control unit (not shown). The communication unit 7 has a plurality of electrical contacts for communicating with a lens CPU 9 described later, and transmits / receives focus adjustment information and photometric information. The lens mounting detection unit 8 detects that the interchangeable lens 2A is mounted using a photodetector or the like.

  The camera body 3 is further provided with an image sensor (not shown) and a signal processing circuit (not shown). An imaging element (not shown) is a photoelectric conversion element that photoelectrically converts an optical image (subject image) formed on the imaging surface, converts it into an electrical signal, and outputs it as an image signal, and is composed of a CMOS image sensor or a CCD sensor. The The signal processing circuit is a region used for focus detection among output signals of all pixels from a CDS / AGC / AD converter (not shown) or a CDS / AGC / AD converter that samples, outputs, and digitizes an output of the image sensor. An AF gate (not shown) that passes the signal of The signal processing circuit then extracts a high frequency component from the signal that has passed through the AF gate and generates an AF evaluation value. The signal processing circuit functions as detection means for detecting a focus signal based on an image signal obtained while moving the focus lens unit 11.

  The AF evaluation value represents the sharpness (AF evaluation value) of an image obtained by processing the output signal from the image sensor, and the sharpness changes depending on the in-focus state of the imaging optical system. ) Is a focus signal for evaluating the in-focus state. The camera CPU 4 performs contrast-based automatic focus adjustment (hereinafter also referred to as “TV-AF”) that moves the focus lens unit 11 to the in-focus position based on the output signal of the signal processing circuit.

  In the interchangeable lens 2A, a lens CPU (control means) 9, a stepping motor 10 as drive means, a focus lens unit 11, a motor driver 12, and a communication unit 13 are provided.

  The lens CPU 9 is responsible for all the controls in the interchangeable lens 2 </ b> A, and is composed of a microcomputer and is equipped with a storage device 15 as storage means for storing the drive correction amount Y of the focus lens unit 11.

  The stepping motor 10 drives the focus lens unit 11 in the optical axis direction of the photographing optical system. The motor for driving the focus lens unit 11 is not limited to the stepping motor 10, and other driving means such as a DC motor, a vibration type motor, and a voice coil motor may be used.

  The focus lens unit 11 includes a focus lens 11a that constitutes a photographing optical system housed in the interchangeable lens 2A, and a lens fixing member (fixed frame) 11b that fixes the focus lens 11a. The focus lens unit 11 further includes a light shielding plate 11c (not shown in FIG. 1). The imaging optical system forms an optical image (subject image) on the imaging surface of an imaging element (not shown). In FIG. 1, the focus lens unit 11 is configured as a single lens, but may be configured as a lens group including a plurality of lenses.

  The motor driver 12 controls the driving of the focus lens 11a by switching the stepping motor 10 on and off. The driving amount of the focus lens 11a is determined by the number of driving pulses output from the motor driver 12 according to a command from the lens CPU9. That is, in this embodiment, the drive correction amount Y is expressed by the number of drive pulses, and this is the same even when the drive means is changed to the other motor described above.

  The communication unit 13 has a plurality of electrical contacts for communicating with the camera CPU 4 and transmits / receives focus adjustment information and photometric information.

  In addition, the interchangeable lens 2A is equipped with a photo interrupter 14 as a detecting means for detecting that the focus lens unit 11 has passed through a specific position within the driveable range. The photo interrupter 14 is a sensor for detecting the origin when the focus lens unit 11 is driven, and is conventionally provided in the interchangeable lens 2A, and does not increase the size of the optical device.

  As shown in FIG. 3 to be described later, the photo interrupter 14 of this embodiment has a light emitting element 14a and a light receiving element 14b. The lens fixing member (fixing frame) 11b can be inserted into and removed from the optical path of the photo interrupter 14. A light shielding plate 11c is fixed. The optical path L of the photo interrupter 14 is perpendicular to the optical axis (not shown) of the photographing optical system, and the light shielding plate 11c of the focus lens unit 11 is disposed perpendicular to the optical path of the photo interrupter 14.

  When the focus lens unit 11 is composed of a lens group, a light shielding plate may be attached to a fixed frame to which any lens of the lens group is fixed.

  The position of the focus lens 11 is managed by counting the number of drive pulses with reference to the detected drive origin. Therefore, an encoder for detecting the position of the focus lens unit 11 and a sensor for detecting the rotation amount of the stepping motor are not used. In this embodiment, the position of the photo interrupter 14 is set to the driving origin at the center of the driveable range of the focus lens unit 11, but may be any position in the driveable range.

  The output of the photo interrupter 14 is at the Hi level if the focus lens unit 11 is located at the infinity end side from the center of the drivable range, and when the focus lens unit 11 is located at the closest end side from the center of the drivable range. The Lo level is arranged, but this may be reversed.

  In TV-AF, after performing wobbling to determine the in-focus direction, hill-climbing driving is performed in the in-focus direction. In wobbling, the center of movement of the focus lens is moved in the direction in which the AF evaluation value is increased while the focus lens unit 11 is reciprocally moved in the optical axis direction by a small period.

  FIG. 2 is a specific operation flowchart of TV-AF. In FIG. 2, “S” is an abbreviation of “Step”, “Y” is an abbreviation of “Yes”, and “N” is an abbreviation of “No”. The same applies to 6 and 8. 2, 4 to 6, and 8 are executed by the camera CPU 4 (or the lens CPU 9), and can be embodied as a program that can be executed by a computer (processor).

  When TV-AF is started, the lens CPU 9 controls the stepping motor 10 to wobble the focus lens 11a in accordance with the drive command from the camera CPU 4 transmitted by the communication unit 7 (S101). Based on the AF evaluation value, the camera CPU 4 moves the wobbling drive center in a direction where the in-focus position will exist. At this time, the camera CPU 4 uses a drive amount for wobbling and a drive correction amount for correcting the drive amount.

  The camera CPU 4 determines that the direction is the in-focus direction when the direction in which it is determined that the in-focus position is present coincides continuously a predetermined number of times. In addition, when the wobbling driving center repeats reciprocation in the same area a predetermined number of times, the camera CPU 4 determines the area as the in-focus position.

  Next, the camera CPU 4 determines whether or not an in-focus determination has been made (S102). If the in-focus direction has not been determined (N in S102), the camera CPU 4 determines whether the in-focus direction has been determined (S103). If the in-focus direction has not been determined (N in S103), S101. Return to.

  On the other hand, when the in-focus direction is determined (Y in S103), the camera CPU 4 controls the stepping motor 10 according to the drive command from the camera CPU 4 to start the hill-climbing drive of the focus lens unit 11 (S104). ).

  Next, the camera CPU 4 determines whether or not the peak of the AF evaluation value has been exceeded, that is, whether or not the AF evaluation value acquired after the current driving is smaller than the AF evaluation value acquired after the previous driving ( S105). When the AF evaluation value exceeds the peak by the predetermined drive amount (Y in S105), the camera CPU 4 moves the focus lens unit 11 in the opposite direction by the predetermined drive amount (S106). When the peak of the AF evaluation value is not exceeded (N in S105), the camera CPU 4 continues the hill-climbing drive.

  Next, the camera CPU 4 determines whether or not the AF evaluation value has reached a peak (S107). If the AF evaluation value peak has not been reached (N in S107), the process returns to S106. If the peak has been reached (Y in S107), the current position becomes the in-focus position, and the process returns to S101 for focus determination. Resume wobbling.

  On the other hand, when the in-focus determination has been made (Y in S102), the camera CPU 4 stops the focus lens unit 11 (S108), and stores the AF evaluation value at the time of the in-focus determination in the storage device 15 (S109). .

  This is a series of operations until the in-focus state is obtained, and then the process proceeds to S110 which is a restart determination process. “Restart determination” is a flow for determining whether or not to perform wobbling (direction determination) again.

  First, the camera CPU 4 acquires the current AF evaluation value (S110). The camera CPU 4 calculates a difference (variation amount) between the previous AF evaluation value stored in the storage device 15 in S109 and the current AF evaluation value acquired in S110, and whether the variation amount is larger than a predetermined value (threshold value). It is determined whether or not (S111). If it is larger (Y in S111), the process returns to S101, and a new in-focus position is searched. If it is equal to or smaller than the predetermined value (N in S111), the in-focus state is maintained, so the focus lens unit 11 is stopped and S110 Returning to, a new AF evaluation value is acquired.

  In wobbling, when the driving amount at the time of wobbling is relatively large with respect to the depth of field of the imaging lens, a large blur occurs in the image signal output from the imaging element, leading to image quality degradation. On the other hand, if the driving amount at the time of wobbling is too small with respect to the depth of field of the imaging lens, there is almost no fluctuation amount of the AF evaluation value, and there is a possibility that the determination of the in-focus direction and the in-focus determination cannot be performed. Therefore, in the wobbling, it is necessary to accurately drive the focus lens unit 11 according to the driving amount instructed from the camera CPU 4. However, when the movement direction of the focus lens unit 11 is reversed (particularly in wobbling), the input movement amount of the focus lens unit 11 is likely to be different from the actual movement amount. For this reason, as described above, it is necessary to correct the drive amount by the drive correction amount.

  FIG. 3A is a diagram showing the relationship between the position of the focus lens 11 a and the output of the photo interrupter 14, and FIG. 3B is the light shielding plate 11 c of the focus lens unit 11 at that time along the optical path L of the photo interrupter 14. The inserted state is shown.

  The photo interrupter 14 of this embodiment is arranged so that the output changes when the focus lens 11a passes through the center of the drivable range. However, actually, the output of the light receiving element 14b of the photo interrupter 14 does not change stepwise from the Lo level to the Hi level at the center of the drivable range (for example, the point A shown in FIG. 3A). As shown in FIG. 3 (a), it changes with a gradient before and after the center of the drivable range.

  This is because, as shown in FIG. 3B, the light shielding plate 11c gradually shields the light path L having a predetermined width from the light emitting element 14a to the light receiving element 14b. In the vicinity of the center of the drivable range, there is an output change region in which the output value continuously changes depending on the position of the focus lens 11a. By reading the output value of the photo interrupter 14 through an A / D converter (not shown) connected to the light receiving element 14b, the change amount of the output value can be detected. Note that when the origin is detected, the output of the photo interrupter 14 is read out via an element that converts the output to 0 or 1, so that the origin position in the output change region is determined.

  As shown in FIG. 3A, when the position of the focus lens 11a is changed from the closest side to the infinite side, a position where the photo interrupter 14 starts to change continuously is defined as M point. At this time, when the focus lens unit 11 is driven with the drive amount a (a> 0), the focus lens 11a is located at the point A, and the amount of change from the point M is ΔVa. Similarly, when the focus lens unit 11 is driven with the drive amount b (b> a> 0), the focus lens 11a is located at the B point, and the change amount from the M point becomes ΔVb. When the focus lens unit 11 is driven with the drive amount c (c> b> a> 0), the focus lens 11a is located at the C point, and the change amount from the M point is ΔVc. There is a relationship of ΔVc> ΔVb> ΔVa between ΔVa to ΔVc. If the position of the focus lens 11a and the amount of change in the output of the photo interrupter 14 are linear, the intervals between the points A, B, and C can be grasped from the difference in the amount of change in the output of the photo interrupter 14.

  Note that the relationship between the output change amount of the photo interrupter 14 and the position of the focus lens 11a is most linear near the center of the output change region. For this reason, it is desirable to inspect the actual movement amount of the focus lens 11a near the center of the output change area of the photo interrupter 14.

  FIG. 4 is a flowchart of a method for inspecting the actual movement amount of the focus lens 11a. FIG. 5 is a graph showing an example of the relationship between the position of the focus lens 11a and the output of the photo interrupter 14 in the inspection method of FIG.

  First, when the main power supply of the camera body 3 is turned on, the camera CPU 4 determines whether or not the interchangeable lens 2A is attached from the output of the lens attachment detection unit 8 (S201). The camera CPU 4 repeats the determination in S201 until it is mounted. If it is mounted (Y in S201), the camera CPU 4 determines whether or not the output of the photo interrupter 14 has become Hi level (S202).

  If the output of the photo interrupter 14 is Hi level (Y in S202), the camera CPU 4 sets the drive direction of the focus lens 11a to the closest direction (S203). If the output of the photo interrupter 14 is Lo level (N in S202), the camera CPU 4 sets the drive direction of the focus lens 11a to the infinity direction (S204).

  In the example of FIG. 5, if the focus lens 11a is at the position P1 in S202, the output of the photo interrupter 14 is at the Lo level, so the camera CPU 4 sets the drive direction of the focus lens 11a to an infinite direction (N in S202). , S204).

  Next, the camera CPU 4 starts driving the focus lens 11a (S205), and then determines whether or not the output change area of the photo interrupter 14 has been reached (S206).

  In the example of FIG. 5, the output change region is represented by R. The output of the photo interrupter 14 is given by a digital value outputted from the A / D converter, and the output change amount of the photo interrupter 14 in the output change region R is given by N. Using the unit voltage value obtained by dividing the voltage value corresponding to the output change amount N by the resolution of the A / D converter, the camera CPU 4 reaches the output change region R when the Lo level value is exceeded by an appropriate voltage value. Judgment can be made.

  If the camera CPU 4 has reached the output change area (Y in S206), the driving of the focus lens 11a is stopped (S207), and if not reached (N in S206), the process returns to S205. The stop position of the focus lens 11a may be the center of the output change area of the photo interrupter 14, or may be a position away from the center. In the example of FIG. 5, the position (first position) of the focus lens 11a at this time is assumed to be the position P2.

  After S207, the camera CPU 4 determines the driving direction of the focus lens unit 11 before stopping in S207 (S208), and performs the inspection driving A if the driving direction is the infinity direction (S209). If the direction is the direction, the inspection drive B is performed (S210). In the example of FIG. 5, the process proceeds to S209.

  FIG. 6 is a flowchart of the inspection drive A for inspecting the actual movement amount of the focus lens 11a, which is executed in S209 of FIG.

  First, the camera CPU 4 clears the drive correction amount Y stored in the storage device 15 to zero (reset to 0) (S301), acquires the current output value A of the photo interrupter 14 and stores it in the storage device 15 ( S302). In the example shown in FIG. 5, the output value V2 corresponding to the position P2 is stored as the output value A (first output value) in S302.

  Next, the camera CPU 4 wobbles the focus lens 11a with a predetermined drive amount X for a predetermined drive time (S303). It is assumed that the wobbling starts from infinity driving and ends at the closest driving. The number of wobbling may be any number.

  In the example shown in FIG. 5, it is assumed that the focus lens 11a moves from the position P2 to the position P3 that is the end of the reciprocating motion, reverses at the position P3, and returns to the position P4 that is the end of the reciprocating motion. As described above, the target drive amount may not correspond to the actual movement amount at the time of reversal. In the example shown in FIG. 5, the focus lens 11a does not return to the position P2 after moving from the position P2 to the position P3. It only returns to P4 (second position). In the reciprocating drive of the focus lens 11a, the end on the position P2 side (end on the first position side) is the position P4 (and positions P5 to P7 described later), not the position P3.

  When the focus lens 11a moves from the position P1 through the position P2 to the position P3, the moving direction is not reversed. Therefore, the position P3 is equal to the position when the focus lens 11a is moved by the drive amount X from the position P2. Easy to do.

  Next, the camera CPU 4 compares the current output value of the photo interrupter 14 with the output value A stored in S302 (S304). When the current output value is larger than the output value A (Y in S304), the camera CPU 4 sets the increment flag to 1 (S305), and the current output value is smaller than the output value A. (N in S304) The increment flag is cleared to zero (S306).

  In the example shown in FIG. 5, in S304, it is determined whether or not the output value V4 (second output value) corresponding to the position P4 is larger than the output value A, and 1 is set to the increment flag from V4> V2. (S304, S305).

  Next, the camera CPU 4 stores (holds) the absolute value of the difference (variation amount ΔV) between the current output value of the photo interrupter 14 and the output value A stored in S302 in the storage device 15 (S307). In the example shown in FIG. 5, ΔV1 (= V4−V2) is stored as ΔV in S307.

  Next, the camera CPU 4 drives the focus lens 11a in the infinity direction with a drive amount obtained by adding Y to the drive amount X (S308). The driving speed is the same as in S303. In the example shown in FIG. 5, Y is cleared in S <b> 301, so that the drive amount X is used here.

  Next, the camera CPU 4 determines whether or not the increment flag is 1 (S309). If the increment flag is 1 (Y in S309), Y is increased by 1 (S310), and if the increment flag is not 1 (N in S309), Y is decreased by 1 (S311). As described above, since the drive amount X and the drive correction amount Y are represented by the number of drive pulses, Y is increased or decreased by one pulse in S310 and S311.

  Next, the camera CPU 4 causes the focus lens 11a to wobble a predetermined number of times with a drive amount obtained by adding the drive correction amount Y to the drive amount X (S312). Note that the wobbling starts from the nearest drive and ends by the nearest drive, and the drive speed is the same as S303.

  In the example shown in FIG. 5, since the driving amount is corrected by driving correction when moving from the position P4 to the position P3 and returning, the focus lens is moved to the position P5 closer to the target position P2 than the position P4. 11a moves.

  Next, the camera CPU 4 compares the variation ΔV stored in S307 with the absolute value of the difference between the current output value of the photo interrupter 14 and the output value A stored in S302 (S313). In the example shown in FIG. 5, since the current output value is the output value V5 corresponding to the position P5, | ΔV2 | = | V5-V2 | is compared with | ΔV (= ΔV1 = V4-V2) |.

  When the fluctuation amount ΔV is smaller (Y in S313), the camera CPU 4 stores the previous Y as the drive correction amount by the storage device 15 (S314), and when the fluctuation amount ΔV is larger (S313). N) Return to S307. In the example shown in FIG. 5, since ΔV2 <ΔV1, the process returns to S307 and ΔV2 is stored as ΔV.

  In this way, the end portion of the focus lens 11a on the wobbling position P2 side approaches the position P2 from the position P4 through the position P5, and then passes through the position P6 and beyond the position P2 to the position P7. Then, at position P7, the result of S313 is Y with respect to position P6. Therefore, the camera CPU 4 stores the drive correction amount Y (previous Y) corresponding to the position P6 as the drive correction amount, and ends.

  In this way, the camera CPU 4 sets the output value V2 of the photointerrupter 14 corresponding to the position P2 during wobbling to the second value of the photointerrupter 14 corresponding to the end portion (second position) of the reciprocating drive on the position P2 side. The drive correction amount Y is updated so that the output value approaches. In other words, the camera CPU 4 repeats the wobbling while updating the drive correction amount Y so that the absolute value of S307 becomes small. By repeating a series of steps (the loop of S307 to S313), the camera CPU 4 causes the absolute value of the repeated S307 to be smallest (when the output value of the photo interrupter 14 is closest to the output value V2). The drive correction amount Y is held. Thereafter, the camera CPU 4 uses the held drive correction amount Y in the TV-AF.

  In the case of equality in S313, ΔV corresponding to the position P6 is equal to ΔV corresponding to the position P7. At this time, whether the previous Y or the current Y is selected is the same.

  Further, in the example of FIG. 5, there is a case where the position P7 is closer to the position P2 than when the position P3 is moved from the initial position P2 and returned. At this time, the increment flag is cleared to 0 (N in S304, S306). Then, ΔV is stored (S308), and since Y = 0, it is driven again by the drive amount X, and since the increment flag is not 1, Y is decreased by one pulse (N in S309, S311). Then, when the position when returning in S313 becomes the position P6 which is on the infinite side of the position P2, the previous Y is stored as the driving amount (S314).

  FIG. 7 is a flowchart of the inspection drive B for inspecting the actual movement amount of the focus lens 11a, which is executed in S210 of FIG.

  First, the camera CPU 4 clears the drive correction amount Y stored in the storage device 15 to zero (reset to 0) (S401), acquires the current output value A of the photo interrupter 14 and stores it in the storage device 15 ( S402).

  Next, the camera CPU 4 wobbles the focus lens 11a with a predetermined drive amount X for a predetermined drive time (S403). Note that the wobbling starts from the closest drive and ends at the infinity drive. The number of wobbling may be any number.

  Next, the camera CPU 4 compares the current output value of the photo interrupter 14 with the output value A stored in S402 (S404). When the current output value is smaller than the output value A (Y in S404), the camera CPU 4 sets the increment flag to 1 (S405), and the current output value is larger than the output value A. (N in S404) The increment flag is cleared to zero (S406).

  Next, the camera CPU 4 stores the absolute value of the difference (variation amount ΔV) between the current output value of the photo interrupter 14 and the output value A stored in S302 in the storage device 15 (S407).

  Next, the camera CPU 4 drives the focus lens 11a in the closest direction with a drive amount obtained by adding Y to the drive amount X (S408). The driving speed is the same as in S403.

  Next, the camera CPU 4 determines whether or not the increment flag is 1 (S409). If the increment flag is 1 (Y in S409), Y is increased by 1 (S410), and if the increment flag is not 1 (N in S409), Y is decreased by 1 (S411). As described above, since the drive amount X and the drive correction amount Y are represented by the number of drive pulses, Y is increased or decreased by one pulse in S410 and S411.

  Next, the camera CPU 4 causes the focus lens 11a to wobble a predetermined number of times with a drive amount obtained by adding the drive correction amount Y to the drive amount X (S412). The wobbling starts from infinity driving and ends at infinity driving, and the driving speed is the same as S403.

  Next, the camera CPU 4 compares the variation ΔV stored in S407 with the absolute value of the difference between the current output value of the photo interrupter 14 and the output value A stored in S402 (S413). When the fluctuation amount ΔV is smaller (Y in S413), the camera CPU 4 stores the previous Y as the drive correction amount by the storage device 15 (S414), and when the fluctuation amount ΔV is larger (S413). N) Return to S407.

  Since the present embodiment uses the photo interrupter 14 for detecting the driving origin of the focus lens 11a, which is provided in advance as a sensor for measuring the actual movement amount of the focus lens 11a, a new position sensor (encoder or the like). Do not need. Further, since the output change region where the output of the photo interrupter 14 changes from the Lo level to the Hi level changes continuously rather than discontinuously like the encoder, the drive correction amount Y can be accurately calculated. Further, the focus correction accuracy can be improved by adding the drive correction amount Y to the target drive amount X to correct the drive amount of the focus lens 11a such as wobbling (particularly in the movement in which the moving direction is reversed). .

  FIG. 8 is a block diagram of the single-lens reflex digital camera 1B of the second embodiment. In FIG. 8, the same members as those in FIG. Unlike the first embodiment, the single-lens reflex digital camera 1B of the present embodiment includes an interchangeable lens 2B instead of the interchangeable lens 2A. The interchangeable lens 2B includes an interchangeable lens in that it includes a temperature detection means (temperature sensor) 16. Different from 2A. The temperature detection means 16 detects the temperature inside the interchangeable lens 2B, that is, the temperature of the environment where the photographing optical system or the focus lens 11a is arranged. The output of the temperature detection means 16 is connected to the lens CPU 9 and provides the detection result to the lens CPU 9.

  FIG. 9 is a flowchart for inspecting the actual movement amount of the focus lens 11a in the second embodiment. 9 adds S211 and S212 to FIG. Since other operations are the same as those in the first embodiment, the description thereof is omitted.

  If the interchangeable lens 2B is attached (S201), the lens CPU 9 proceeds to S202 if the temperature detected by the temperature detection means 16 exceeds the set range at regular time intervals (Y in S211). On the other hand, if it is within the setting range (N in S211), the lens CPU 9 proceeds to S202 when the voltage value for driving the stepping motor 10 supplied from the camera body 3 is less than or equal to the set value (below the threshold value). If greater than the value, the process returns to S211.

  In this embodiment, the inspection drive is performed when the temperature detected by the temperature detection means 16 is outside the set range or when the voltage value for driving the stepping motor 10 supplied from the camera body 3 is equal to or less than the set value. To do. Therefore, when there is a temperature change or voltage value change, the difference between the actual movement amount of the focus lens 11a and the target drive amount is automatically and accurately measured, and a drive correction amount for correcting the difference is accurately calculated. it can.

  The temperature detecting means 16 is conventionally provided in an interchangeable lens for the purpose of correcting the optical information such as the focal length according to the detected temperature. For this reason, since the present Example also aims at multi-functionalization using the member currently arrange | positioned and does not require a new member, the enlargement of an optical apparatus can be prevented.

  The drive correction amount acquisition time for calibrating the movement amount of the focus lens 11a is not limited to the first and second embodiments. For example, the inspection drive may be performed periodically (every fixed time) after the focus lens 11a is continuously driven for a long time when the main power of the camera body 3 is turned on with the interchangeable lens mounted. Good. When performing periodically, a time-counting means (not shown) provided in the optical device is used, and when performing main power-on, a power-on means (not shown) is used.

  In the first and second embodiments, the number of drive pulses of the stepping motor 10 is changed in order to correct the difference between the actual moving amount of the focus lens 11a and the target drive amount. Good.

  Note that a known method can be applied to the method of acquiring the drive correction amount Y and correcting the drive amount X of the focus lens 11a (including the case of correcting the movement amount of the center of the reciprocating motion). In the present embodiment, detailed description thereof is omitted. Further, the drive correction amount Y can be applied to the inversion drive of the focus lens 11a even if it is not wobbling.

  In this embodiment, the photo interrupter 14 is used to detect the origin position of the focus lens 11a. However, the origin position of the focus lens 11a can also be detected using a resistor that can detect the position of the focus lens 11a by continuously changing the output without using a photo interrupter. For this reason, the present invention is applicable even when such a detection means is used.

  The drive correction amount Y may be changed according to the drive amount X. In this case, different drive correction amounts Y may be held for different drive amounts X, a drive correction amount corresponding to the drive amount to be used may be selected, or the drive correction amount may be calculated by interpolation.

  As mentioned above, although the preferable Example of this invention was described, this invention is not limited to these Examples, A various deformation | transformation and change are possible within the range of the summary.

  Optical instruments can be applied to applications that require focus adjustment.

1A, 1B SLR digital camera (optical equipment)
2A, 2B Interchangeable lens (optical equipment)
4 Camera CPU
9 Lens CPU
11a Focus lens 14 Photo interrupter (detection means)
16 Temperature detection means R Output change area

Claims (7)

An optical device that performs focus adjustment by wobbling a focus lens that constitutes a photographing optical system that forms an optical image in the optical axis direction of the photographing optical system,
A motor for driving the focus lens;
Detecting means having an output change region in which the origin is detected when driving the focus lens and the output continuously changes;
The focus lens is wobbled from the first position in the output change region, and the first output value of the detection means corresponding to the first position of the focus lens is changed to the reciprocating drive on the first position side. The wobbling is repeated while updating the drive correction amount for correcting the drive amount applied to the motor so that the second output value of the detection means corresponding to the second position of the focus lens which is the end portion approaches, Control means for holding the drive correction amount when the output value of 2 is closest to the first output value, and using the held drive correction amount for the focus adjustment;
An optical apparatus comprising: The optical device is configured such that an interchangeable lens that houses the photographing optical system is detachable,
The optical apparatus according to claim 1, wherein the control unit calculates the drive correction amount when the interchangeable lens is attached. The optical apparatus further includes temperature detection means for detecting the temperature of the environment in which the focus lens is disposed,
The optical apparatus according to claim 1, wherein the control unit calculates the drive correction amount when the temperature detected by the temperature detection unit is out of a set range. The optical apparatus further includes a time measuring means,
The optical apparatus according to claim 1, wherein the control unit periodically calculates the drive correction amount using the time measuring unit. The optical device further includes power-on means for the optical device,
The optical apparatus according to claim 1, wherein the control unit calculates the drive correction amount when a main power is turned on by the power-on unit.   The optical apparatus according to claim 1, wherein the control unit calculates the drive correction amount when a voltage value for driving the motor is equal to or less than a set value. A control method for an optical apparatus that performs focus adjustment by wobbling a focus lens constituting a photographing optical system that forms an optical image in the optical axis direction of the photographing optical system via a motor,
Holds the first output value of the detection means when the focus lens is disposed at the first position in the output change region where the output of the detection means for detecting the origin when driving the focus lens continuously changes. And steps to
The focus lens is wobbled from the first position in the output change region, and a second position of the detection means corresponding to a second position of the focus lens that is an end of reciprocating drive on the first position side. Holding the absolute value of the difference between the output value and the first output value, repeating the wobbling while updating the drive correction amount for correcting the drive amount to be given to the motor so that the absolute value becomes smaller;
Holding the drive correction amount when the absolute value becomes the smallest due to repeated wobbling;
Using the held drive correction amount for the focus adjustment;
A method for controlling an optical apparatus, comprising: