JP5347275B2 - Aperture driving device and lens barrel - Google Patents

Description

  The present invention relates to an aperture driving device and a lens barrel.

  For example, in a camera system that controls the aperture of an aperture mechanism attached to a lens barrel with an arm that extends from the camera body of a single-lens reflex camera to the lens barrel, it is difficult to perform a so-called “tilting” operation. The “tilting” operation is an operation of shifting the center of the lens from the center of the imaging surface or adjusting the angle of the optical axis of the lens with respect to the imaging surface.

  In view of this, an electrically driven diaphragm mechanism (Patent Document 1) that controls a diaphragm by mounting a diaphragm mechanism such as a motor actuator in a lens barrel has been developed. In this type of conventional camera system, an abnormality in aperture drive control is detected as follows. That is, conventionally, the number of pulses supplied to the stepping motor at the time of narrowing is compared with the number of pulses supplied to the stepping motor when the aperture is returned to the open state, and the comparison result indicates whether the diaphragm drive device is normal or abnormal. Deciding. If it is not normal but abnormal, a warning is displayed to the user.

  However, conventionally, if the number of pulses of the stepping motor at the time of narrowing is different from that at the time of opening, a warning signal will be issued. Sometimes. For example, when a stepping motor is assembled in the aperture driving device, the number of pulses of the motor does not correspond to the detection position of the aperture opening, so that there is an error of several pulses in the normal range.

  Further, when there is a difference between the origin position of the aperture blade and the driving start pattern of the stepping motor, the aperture accuracy is deteriorated.

  Further, conventionally, the aperture operation is performed by an instruction from the camera body. Even if the target aperture position is the same, the aperture time to the target aperture position differs for each lens barrel. This is because the size of the lens, the size of the diaphragm, and the like are different for each lens barrel. Therefore, it is necessary to set the release time lag from the release switch on to the actual exposure in accordance with the slowest narrowing time, and it is difficult to optimize the release time lag.

Furthermore, conventionally, when the diaphragm is driven from the narrowed state to the open state, the stepping motor may step out for some reason and the diaphragm blades may not be in the open standby position. In such a case, since it is not possible to calculate how much the diaphragm blades should be driven, the next shooting may not be possible.
JP-A-6-102558

  The present invention has been made in view of such a situation, and an object thereof is to provide an aperture driving device and a lens barrel capable of controlling an aperture value with high accuracy.

In order to achieve the above object, a diaphragm driving device according to the present invention includes:
A diaphragm mechanism (26) capable of adjusting an area of an aperture through which light passes;
A drive unit (24) for driving the aperture mechanism (26);
A position detection sensor (25) for detecting an open position (Ps) of the aperture mechanism (26);
When the open position (Ps) of the aperture mechanism (26) is detected by the position detection sensor (25) during driving by the drive unit (24), the aperture mechanism (26) is moved to the open position ( And a control unit (15) for calculating a drive amount (Pc) for moving from Ps) to the target aperture position (Px).

  In the aperture driving device of the present invention, when the open position (Ps) of the aperture mechanism (26) is detected by the position detection sensor (25) during driving by the drive unit (24), the aperture mechanism (26) is operated. A drive amount (Pc) for moving from the open position (Ps) to the target aperture position (Px) is calculated. Therefore, when there is an error in the drive amount (Pc) from the open standby position (Pi) to the target aperture position (Px), the drive amount (Pc) can be corrected at the open position (Ps). Thus, the precision of the aperture drive control is improved.

Preferably, the aperture of the aperture mechanism (26) is movable between an open standby position (Pi) and a predetermined aperture position,
Between the opening standby position (Pi) and the predetermined narrowing position, the opening position (Ps) exists on the side closer to the opening standby position (Pi) than the predetermined narrowing position.

  The aperture mechanism (26) is preferably driven to the target aperture position (Px) after returning to the open standby position (Pi), and passes through the open position (Ps) on the way, and at the open position (Ps). It is preferable that recalculation of the drive amount (Pc) is performed, and the aperture mechanism (26) is driven with the drive amount (Pc).

  For example, the drive unit (24) detects the open position (Ps) by the position detection sensor (25) after the drive of the aperture mechanism (26) from the open standby position (Pi). After that, it is preferable that a drive signal corresponding to the drive amount (Pc) is received from the control unit (15).

  Preferably, the drive unit (24) moves from the control unit (15) so as to move the opening of the aperture mechanism (26) from the open standby position (Pi) to the target aperture position (Px). A narrowing drive signal is received.

  From the opening standby position (Pi) to the opening position (Ps) at the timing when the position detection sensor (25) detects that the opening of the aperture mechanism (26) has passed the opening position (Ps). The required actual aperture drive signal is counted, and if the counted drive signal is not within a predetermined range, the drive signal sent from the control unit (15) to the drive unit (24). The aperture driving device may have first correcting means (S7) for correcting the above.

  The drive unit (24) detects the open position (Ps) by the position detection sensor (25) after starting the drive of the aperture mechanism (26) from the target aperture position (Px). Later, a drive signal corresponding to a predetermined drive amount (Po) up to the opening standby position (Pi) may be received from the control unit (15). That is, any signal received by the drive unit (24) from the control unit (15) may be used until the open position (Ps) is detected.

  The drive unit (24) receives an opening drive signal from the control unit (15) so as to move the opening of the aperture mechanism (26) from the target aperture position (Px) to the opening standby position (Pi). You may make it receive.

  From the target aperture position (Px) to the open position (Ps) when the position detection sensor (25) detects that the opening of the aperture mechanism (26) has passed through the open position (Ps). The actual opening drive signal required is counted, and the counted drive signal is not within the range of the expected drive signal required from the target aperture position (Px) to the opening position (Ps). The aperture drive device may have second correction means (S27) for correcting the drive signal sent from the control unit (15) to the drive unit (24).

  A drive signal sufficient to move the aperture of the aperture mechanism (26) from the target aperture position (Px) to the open standby position (Pi) is sent from the control unit (15) to the drive unit (24). If the position detection sensor (25) does not detect the opening position (Ps) of the diaphragm mechanism (26), the opening is again performed from the target diaphragm position (Px). The diaphragm drive device may further include retry means (S30) for outputting a drive signal sufficient to move to the standby position (Pi) from the control unit (15) to the drive unit (24).

  When a drive signal sufficient to move from the target aperture position (Px) to the open standby position (Pi) is input from the control unit (15) to the drive unit (24), the position detection sensor ( If the open position (Ps) of the aperture mechanism (26) is not detected in 25), it is considered that the motor has stepped out, for example. In such a case, a drive signal sufficient to move again from the target aperture position (Px) to the open standby position (Pi) using retry means is sent from the control unit (15) to the drive unit (24). By outputting, the aperture can be returned to the open position (Ps). If the diaphragm cannot be returned to the open position (Ps), the diaphragm mechanism (26) is abnormal, and a warning is displayed.

  The actual drive signal required to move the aperture mechanism (26) from the open position (Ps) to the target aperture position (Px) and the target aperture position (Px) to the open position (Ps) The diaphragm driving device further includes warning means (S32) for outputting a warning signal when the difference is calculated by comparing with an actual drive signal required for the calculation and the difference exceeds a predetermined range. You may have. By providing redundancy to the conditions for detecting the difference between these drive signals, a warning can be issued only when there is an abnormality in the diaphragm operation such as motor step-out.

  A lens barrel according to the present invention has any one of the above-described diaphragm driving devices. Preferably, the lens barrel receives an estimated driving time for actually moving the aperture mechanism (26) to the target aperture position (Px) after receiving a signal indicating an aperture execution instruction from the camera body. Drive time prediction means (S2, S22) for transmission is provided. By transmitting the expected driving time to the camera body, the release time lag can be optimized.

  In the above description, in order to explain the present invention in an easy-to-understand manner, the description has been made in association with the reference numerals of the drawings showing the embodiments, but the present invention is not limited to this. The configuration of the embodiment described later may be improved as appropriate, or at least a part of the configuration may be replaced with another component. Further, the configuration requirements that are not particularly limited with respect to the arrangement are not limited to the arrangement disclosed in the embodiment, and can be arranged at a position where the function can be achieved.

Hereinafter, the present invention will be described based on embodiments shown in the drawings.
FIG. 1 is a block diagram of a camera system having a lens barrel provided with an aperture driving device according to an embodiment of the present invention.
2 to 4 are flowcharts of an aperture driving device according to an embodiment of the present invention.
FIG. 5 is a schematic diagram showing the relationship among the open position, open standby position, and target throttle position of the throttle mechanism shown in FIG.
FIG. 6 is a graph showing position detection at the open position.

  As shown in FIG. 1, the camera system of this embodiment includes a camera body 1 and a lens barrel 2. The camera body 1 includes a power source 3, a DC-DC converter 4, and a body CPU 5 therein. The voltage supplied from the power supply 3 is made a constant voltage by the DC-DC converter 4 and becomes the logic system power supply voltage Vdd. The voltage Vdd is applied to the body CPU 5 and to the lens CPU 15 through the transistor 6 and the contacts 10 and 14. The voltage application to the lens CPU 15 is controlled by turning on / off the transistor 6 based on a signal from the body CPU 5.

  The lens barrel 2 is detachably connected to the camera body 1, and signal communication or power supply is performed through the contacts 9 to 14 of the connection portion. The contact 9 is a contact for supplying a voltage to a power drive device that requires a relatively large power system power supply voltage Vcc, such as a motor driver 19 mounted inside the lens barrel 2.

  The contacts 11 to 13 are contacts for performing data communication between the body CPU 5 and the lens CPU 15. The contacts 10 and 14 are contacts for supplying the logic system power supply voltage Vdd to the lens CPU 15.

  A transistor 7 and a resistor 8 are connected to the internal circuit of the camera body 1 from the power source 3 to the contact 9. The transistor 7 is controlled by a signal from the body CPU 5 and controls the power system power supply voltage Vcc to the lens barrel 2. For example, when the transistor 7 is turned on based on a signal from the body CPU 5, the voltage from the power supply 3 is directly applied to the motor driver 19 through the contact 9 as the power system power supply voltage Vcc.

  The lens barrel 2 is equipped with a lens (not shown) and a diaphragm mechanism 26 that adjusts the aperture area of light passing through the lens. The diaphragm blades of the diaphragm mechanism 26 are driven by a stepping motor 24, and the motor 24 is controlled by a motor driver 19 based on a signal from the lens CPU 15.

  The aperture mechanism 26 drives the aperture blades to control the aperture. The aperture opening position is detected by the position detection sensor 25, and the detection signal is transmitted to the lens CPU 15 via the aperture detection circuit 18.

  The lens barrel 2 of this embodiment is equipped with an aperture setting unit 17 such as an aperture ring for setting the aperture. The diaphragm ring is rotatably mounted on a fixed barrel of the lens barrel together with a zoom ring for controlling the zoom magnification of the lens. The aperture value data set by the aperture setting unit 17 is input to the lens CPU 15.

  When the aperture data can be communicated at the contacts 11 to 13 between the body CPU 5 and the lens CPU 15, the aperture value data input to the lens CPU 15 is communicated to the body CPU 5.

  The lens barrel 2 is provided with a stop switch 23 so that it can be operated from the outside. The narrowing switch 23 operates the switch 22 connected between the power line L1 between the contact 9 and the motor driver 19 and the earth ground E. The switch 22 is a normally open switch, and is turned on only while the narrowing switch 23 is pressed, and connects between the power supply line L1 and the earth ground E. When the narrowing switch 23 is not pushed, the switch 22 is turned off, and the power supply line L1 and the earth ground E are not connected.

  A diode 21 is connected between the switch 22 and the power supply line L1, so that a current flows only in one direction. The lens CPU 15 is connected to the line between the diode 21 and the switch 22 via the diode 20 so that the lens CPU 15 can monitor whether or not the switch 22 is pressed.

  In the camera system shown in FIG. 1, when the camera body 1 is turned on, or when some operation is performed to cancel the sleep mode, the body CPU 5 activates the transistor 6 and passes the contact 10 to the lens CPU 15. A power supply voltage Vdd is supplied. The sleep mode is a mode in which the power supplied from the power source to each component is reduced (including zero) when the camera body 1 or the lens barrel 2 is not operated for a predetermined time or longer. The sleep mode is canceled when the operator operates the switches of the camera body 1 or the aperture switch 23 of the lens barrel 2. That is, the camera body 1 returns from the timer off.

  Whether or not the switches of the camera body 1 are operated can be easily detected by the body CPU 5 connected to the switches. The return operation from the timer-off when the operator operates the aperture switch 23 of the lens barrel 2 is as follows.

  That is, when the narrowing switch 23 is pressed, the switch 22 is turned on, and a current flows by applying the power supply voltage Vcc through the diode 21. For this reason, the voltage level of the power supply voltage Vcc of the power supply line pulled up by the resistor 8 is lowered. At that time, transistor 7 is still off. Since the body CPU 5 monitors the power supply voltage Vcc, when the voltage level of the power supply voltage Vcc falls below the threshold value, the body CPU 5 returns the camera body 1 from the timer off and cancels the sleep mode. That is, the transistor 6 is turned on to supply the power supply voltage Vdd to the lens CPU 15.

  At the same time, the body CPU 5 and the lens CPU 15 communicate with each other through the contacts 11 to 13, and if necessary, the transistor 7 is turned on so that a voltage can be supplied to the power driving device such as the motor driver 19.

  The aperture switch 23 has a function of canceling the sleep mode and is a switch for setting an aperture value in the lens barrel 2 when data communication regarding aperture information cannot be performed between the camera body 1 and the lens barrel 2. It also has the function as In the following description, a case where data communication regarding aperture information can be performed between the camera body 1 and the lens barrel 2 will be described. However, when data communication regarding aperture information cannot be performed, the same applies except for matters where data communication cannot be performed. Control is possible.

  FIG. 2 is a flowchart showing the aperture control operation of the lens CPU 15 when the camera body 1 and the lens barrel 2 shown in FIG. 1 can perform data communication regarding aperture information. As shown in step S1 shown in FIG. 2, when the lens CPU 15 shown in FIG. 1 receives the aperture execution command from the body CPU 5, the lens CPU 15 drives the motor according to the target aperture value in step S2 shown in FIG. The number of pulses Pc and the expected narrowing time Tc are calculated.

  As a premise of step S2 shown in FIG. 2, the opening of the diaphragm blade 26a of the diaphragm mechanism 26 shown in FIGS. 1 and 5 is returned so as to be located at the open standby position Pi that is opened to the maximum. Yes. Immediately before the narrowing, the opening of the diaphragm blade 26a is positioned at the open standby position Pi. The aperture of the aperture blade 26a is movable between the open standby position Pi and the minimum aperture position (position where the area of the aperture of the aperture mechanism 26 is minimum) Pmin, and from the open standby position Pi to the minimum aperture position. In the middle of Pmin, the open position Ps exists on the side close to the open standby position Pi.

  As shown in FIGS. 5 and 6, the number of motor drive pulses Pc corresponding to the target aperture value is the stepping motor required for moving the aperture of the aperture blade 26a from the open standby position Pi to the target aperture position Px. The number of drive pulses is 24. The predicted narrowing time Tc is a time required for moving the diaphragm blade 26a from the open standby position Pi to the target throttle position Px.

  As shown in FIG. 6, the driving speed v of the diaphragm blade 26a gradually changes during the initial and final movements of moving the diaphragm blade 26a from the open standby position Pi to the target diaphragm position Px. v0. The predicted narrowing time Tc is preferably determined in consideration of the speed change of the driving speed v of the diaphragm blades 26a.

  In step S3 shown in FIG. 2, the expected narrowing time Tc calculated by the lens CPU 15 shown in FIG. 1 is transmitted to the body CPU 5. Next, in step S4 shown in FIG. 2, the lens CPU 15 shown in FIG. 1 sends a signal to the motor driver 19 to drive the stepping motor 24 one step and drive the aperture blade 26a in the aperture direction. Thereafter, in step S5 shown in FIG. 2, one pulse number is subtracted from the decrement number NPc corresponding to the drive pulse number Pc.

  Next, in step S6 shown in FIG. 2, it is determined whether or not the position detection sensor 25 shown in FIG. 1 has detected the open position Ps shown in FIG. 5. If not, step S8 shown in FIG. To determine whether or not the decrement number NPc is zero. The case where the decrement number NPc is 0 indicates a state where the driving of the stepping motor 24 is completed with the drive pulse number Pc corresponding to the target aperture value.

  If the driving has not been completed with the driving pulse number Pc, the process returns from step S8 to step S4 shown in FIG. 2, and steps S4 to S8 are repeated. When the position detection sensor 25 shown in FIG. 1 detects the open position Ps shown in FIG. 5 in step S6, the output of the sensor 25 is switched from Low to High as shown in FIG. Go to step S7.

  In step S7, the lens CPU 15 shown in FIG. 1 compares the actual number of drive steps required for the movement of the diaphragm blade 26a shown in FIG. 5 from the open standby position Pi to the open position Ps with the expected drive step number. Based on the comparison, the drive pulse number Pc is corrected. For example, assume that when the expected number of drive steps required for the movement from the open standby position Pi to the open position Ps is 3 steps, 4 steps are actually required.

  In such a case, the aperture blade 26 does not reach the target aperture position Px unless the drive pulse number Pc is increased by one step. This is because the drive pulse number Pc is calculated assuming that the number of drive steps required for the movement from the open standby position Pi to the open position Ps is 3 steps. Therefore, in such a case, the drive pulse number Pc is corrected at step S7 shown in FIG.

  In step S8, as described above, it is determined whether or not the decrement number NPc is 0. If the decrement number NPc is 0, the process proceeds to step S9 shown in FIG. In step S9, the lens CPU 15 shown in FIG. 1 detects, based on the output from the position detection sensor 25, whether or not the opening of the aperture blade 26a shown in FIG. 5 has passed the open position Ps.

  When it is determined that the opening of the aperture blade 26a shown in FIG. 5 does not pass through the open position Ps, the stepping motor 24 shown in FIG. 1 has been driven with the number of drive pulses Pc corresponding to the target aperture value. Is the case where the open position Ps is not detected. That is, this is an abnormal state in which the opening of the diaphragm blade 26a shown in FIG. In such a case, the process goes to step S10 shown in FIG. 2, and the lens CPU 15 shown in FIG. 1 sets the aperture drive error flag F1 to 1 and transmits the error flag F1 to the body CPU 5.

  The body CPU 5 displays the warning on the display device of the camera body 1 by receiving the error flag F1. The contents of the warning display are contents indicating that there is an aperture drive error. The body CPU 5 may stop the normal photographing operation by receiving the error flag F1 or may continue the photographing operation itself.

  After step S9 and step S10 shown in FIG. 2, the lens CPU 15 shown in FIG. 1 ends the narrowing-down operation in step S11 shown in FIG. After that, the normal shooting operation by the body CPU 5 is started.

  FIG. 3 shows an operation when the lens CPU 15 shown in FIG. 1 receives an open reset execution command from the body CPU 5. That is, FIG. 3 shows a control flow in the case where the aperture of the diaphragm blade 26a shown in FIG. 5 is at the target diaphragm position Px, and is returned from there to the open standby position Pi.

  Specifically, when the lens CPU 15 shown in FIG. 1 receives an open reset execution command from the body CPU 5 in step S21 shown in FIG. 3, the process proceeds to step S22. In step S22, the motor drive pulse number Po required for returning the aperture of the aperture blade 26a shown in FIG. 5 from the current aperture position Px to the open standby position Pi and the expected aperture time To are calculated.

  The calculation of the motor drive pulse number Po and the predicted narrowing time To is performed in the same manner as the calculation of the motor drive pulse number Pc and the predicted narrowing time Tc in step S2 shown in FIG.

  Next, in step S23 shown in FIG. 3, the predicted narrowing time To calculated by the lens CPU 15 shown in FIG. 1 is transmitted to the body CPU 5 in the same manner as in step S3 shown in FIG. Next, in step S24 shown in FIG. 3, the lens CPU 15 shown in FIG. 1 sends a signal to the motor driver 19 to drive the stepping motor 24 one step and drive the aperture blade 26a in the opening direction. Thereafter, in step S25 shown in FIG. 3, one pulse number is subtracted from the decrement number NPo corresponding to the drive pulse number Po.

  Next, in step S26 shown in FIG. 3, it is determined whether or not the position detection sensor 25 shown in FIG. 1 has detected the open position Ps shown in FIG. 5. If not, step S28 shown in FIG. To determine whether the decrement number NPo is zero or not. The case where the decrement number NPo is 0 indicates a state in which the driving of the stepping motor 24 is completed with the drive pulse number Po. When the aperture mechanism is operating normally, the aperture of the aperture blade 26a should have returned to the open standby position Pi.

  If the driving has not been completed with the number of driving pulses Po, the process returns from step S28 shown in FIG. 3 to step S24, and steps S24 to S28 are repeated. If the position detection sensor 25 shown in FIG. 1 detects the open position Ps shown in FIG. 5 in step S26, the output of the sensor 25 is switched from High to Low as shown in FIG. Go to step S27.

  In step S27, the lens CPU 15 shown in FIG. 1 compares the actual drive step number required for the movement of the stop blade 26a shown in FIG. 5 from the stop position Px to the open position Ps with the expected drive step number. Based on the comparison, the drive pulse number Po is corrected. For example, when the expected number of drive steps required for the movement from the aperture position Px to the open position Ps is 10, assume that 12 steps are actually required.

  In such a case, the diaphragm blade 26 does not reach the open standby position Pi unless the drive pulse number Po is further increased by two steps. This is because the drive pulse number Po is calculated on the assumption that the number of drive steps required for the movement from the aperture position Px to the open position Ps is 10 steps, and that the drive pulse number Po is 3 steps from the open position Ps to the open standby position Pi. Because. Therefore, in such a case, the drive pulse number Po is corrected in step S7 shown in FIG. 2, and at the same time, the decrement number NPo is also corrected, and the process goes to step S28.

  In step S28, as described above, it is determined whether or not the decrement number NPo is 0. If the decrement number NPo is 0, the process proceeds to step S29 shown in FIG. In step S29, the lens CPU 15 shown in FIG. 1 detects, based on the output from the position detection sensor 25, whether or not the aperture of the diaphragm blade 26a shown in FIG.

  When it is determined that the opening of the diaphragm blade 26a shown in FIG. 5 does not pass through the open position Ps, the open position Ps is set even if the stepping motor 24 shown in FIG. This is the case when it is not detected. That is, this is an abnormal state in which the aperture of the diaphragm blade 26a shown in FIG. 5 is on the diaphragm side and has not returned to the open standby position Pi. In such a case, the process goes to step S30 shown in FIG. 3 to perform a retry operation. The retry operation is shown in FIG. 4 and will be described later.

  If the lens CPU 15 shown in FIG. 1 determines in step S29 that the opening of the aperture blade 26a shown in FIG. 5 has passed through the open position Ps based on the output from the position detection sensor 25, it is shown in FIG. Go to step S31. In step S31, the actual number of drive pulses Pc ′ required for the lens CPU 15 shown in FIG. 1 to move from the open position Ps shown in FIG. 5 to the target aperture position Px and from the target aperture position Px to the open position Ps are shown. The difference is calculated by comparing with the actual driving pulse number Po ′ required for the return movement.

  If the absolute value of the difference exceeds the predetermined number of pulses Pa, the process goes to step S32 shown in FIG. 3, and if not, the process goes to step S33. The predetermined number of pulses Pa is not particularly limited, but is 3 to 8 pulses, for example. In step S32 shown in FIG. 3, the lens CPU 15 shown in FIG. 1 sets the aperture error flag F2 to 1, and transmits the error flag F2 to the body CPU 5. The case where the absolute value of the difference exceeds the predetermined number of pulses Pa in step S31 shown in FIG. 3 is a case where there is a problem such as the stepping motor 24 shown in FIG.

  In such a case, the body CPU 5 shown in FIG. 1 issues an error display warning based on the reception of the narrowing-down error flag F2. The contents of the warning display are contents indicating that the photographed image was photographed with a narrowing error. The body CPU 5 waits for the next photographing operation after receiving the error flag F2.

  The case where the absolute value of the difference is smaller than the predetermined number of pulses Pa in step S31 shown in FIG. Further, also after step S32, the lens CPU 15 shown in FIG. 1 ends the aperture mechanism opening reset operation in step S33 shown in FIG. The body CPU 5 shown in FIG. 1 waits for the next shooting operation.

  Next, details of the retry operation shown in FIG. 3 will be described with reference to FIG. When the retry operation starts in step S41 shown in FIG. 4, in step S42, the lens CPU 15 shown in FIG. 1 sets the open reset error flag F3 to 1, and stores the error flag F3. In step S42, the driving step number Po for returning to the open side obtained in step S22 shown in FIG. 3 is reset. At the same time, the decrement number NPo is also returned to the original number of steps.

  Next, in step S43 shown in FIG. 4, the lens CPU 15 shown in FIG. 1 sends a signal to the motor driver 19 to drive the stepping motor 24 one step and drive the aperture blade 26a in the opening direction. Thereafter, in step S44 shown in FIG. 4, one pulse number is subtracted from the decrement number NPo corresponding to the drive pulse number Po.

  Next, in step S45 shown in FIG. 4, it is determined whether or not the position detection sensor 25 shown in FIG. 1 has detected the open position Ps shown in FIG. 5. If not, step S47 shown in FIG. To determine whether the decrement number NPo is zero or not. The case where the decrement number NPo is 0 indicates a state in which the stepping motor 24 is driven again by the drive pulse number Po and finished. When the aperture mechanism is operating normally in the retry operation, the aperture of the aperture blade 26a should have returned to the open standby position Pi.

  In the retry operation, when the driving is not finished with the number of driving pulses Po, the process returns from step S43 shown in FIG. 4 to step S43, and steps S43 to S47 are repeated. When the position detection sensor 25 shown in FIG. 1 detects the open position Ps shown in FIG. 5 in step S45, the output of the sensor 25 is switched from High to Low as shown in FIG. Go to step S46.

  In step S46, the lens CPU 15 shown in FIG. 1 compares the actual drive step number required for the movement of the stop blade 26a shown in FIG. 5 from the stop position Px to the open position Ps with the expected drive step number. Based on the comparison, the drive pulse number Po is corrected. For example, when the expected number of drive steps required for the movement from the aperture position Px to the open position Ps is 10, assume that 12 steps are actually required.

  In such a case, the diaphragm blade 26 does not reach the open standby position Pi unless the drive pulse number Po is further increased by two steps. This is because the drive pulse number Po is calculated on the assumption that the number of drive steps required for the movement from the aperture position Px to the open position Ps is 10 steps, and that the drive pulse number Po is 3 steps from the open position Ps to the open standby position Pi. Because. Therefore, in such a case, the drive pulse number Po is corrected at step S7 shown in FIG.

  In step S47, as described above, it is determined whether or not the decrement number NPo is 0. If the decrement number NPo is 0, the process proceeds to step S48 shown in FIG. In step S48, the lens CPU 15 shown in FIG. 1 detects whether or not the opening of the aperture blade 26a shown in FIG. 5 has passed the open position Ps based on the output from the position detection sensor 25.

  The case where it is determined that the opening of the diaphragm blade 26a shown in FIG. 5 does not pass through the open position Ps is the open position even if the stepping motor 24 shown in FIG. 1 is driven again with the drive pulse number Po. This is a case where Ps is not detected. That is, this is an abnormal state in which the aperture of the diaphragm blade 26a shown in FIG. 5 is on the diaphragm side and has not returned to the open standby position Pi. In such a case, the process goes to step S51 shown in FIG. 4, and the lens CPU 15 shown in FIG. 1 transmits an open reset error F3 = 1 to the body CPU 5. Thereafter, the process returns from step S50 shown in FIG. 4 to step S33 shown in FIG. 3, and the open reset end operation shown in step S33 described above is performed.

  The case where the opening reset error F3 = 1 is transmitted to the body CPU 5 in step S51 indicates that the opening of the aperture blade 26a shown in FIG. 1 does not return to the opening standby position Pi even in the retry operation. In such a case, since the next normal photographing operation cannot be performed, the body CPU 5 shown in FIG. 1 displays, for example, a warning signal indicating that normal photographing is not possible based on the open reset error F3 = 1.

  In step S48 shown in FIG. 4, when the lens CPU 15 shown in FIG. 1 determines that the opening of the aperture blade 26a shown in FIG. Go to step S49 shown in FIG. In step S49, the lens CPU 15 shown in FIG. 1 returns the open reset error flag F3 to 0, and does not transmit the open reset error F3 = 1 to the body CPU 5.

  If it is determined that the opening of the diaphragm blade 26a shown in FIG. 5 has passed the open position Ps, it is considered that the opening of the diaphragm blade 26a shown in FIG. 5 has returned to the open standby position Pi by the retry operation. is there. In such a case, the process returns from step S50 shown in FIG. 4 to step S33 shown in FIG. 3, and the open reset end operation shown in step S33 described above is performed.

  In the lens barrel 2 having the aperture driving device according to the present embodiment, when the open position Ps of the aperture blade 26a is detected by the position detection sensor 25 shown in FIG. 1 in steps S6 and S7 shown in FIG. The motor driving pulse number Pc for moving the diaphragm blade 26a from the open position Ps to the target diaphragm position Px is corrected. Therefore, when there is an error in the number of drive pulses from the open standby position Pi to the open position Ps, it becomes possible to accurately correct the number of drive pulses from the open position Ps to the target aperture position Px. The accuracy of control is improved.

  Further, in the present embodiment, in step S31 shown in FIG. 3, from the actual drive pulse number Pc ′ required for moving from the open position Ps shown in FIG. 5 to the target aperture position Px and the target aperture position Px. The difference is calculated by comparing with the actual number of driving pulses Po ′ required to move back to the open position Ps. In this embodiment, by giving redundancy to the predetermined number of pulses Pa, which is a condition for detecting the difference between these drive signals, a warning is issued only when there is a particular abnormality in the diaphragm operation such as motor step-out. be able to.

  Furthermore, in the present embodiment, a sufficient drive signal Po is transmitted from the lens CPU 15 shown in FIG. 1 to the motor driver 19 to move again from the target aperture position Px to the open standby position Pi using the retry operation shown in FIG. The aperture can be returned to the open standby position Pi. If the aperture cannot be returned to the open standby position Pi, there is an abnormality in the aperture mechanism, and a warning is displayed in step S51 shown in FIG.

  Furthermore, in this embodiment, in step S3 shown in FIG. 2 or step S23 shown in FIG. 3, the expected driving time Tc for moving the opening of the aperture blade 26a to the target aperture position Px, or its open return drive. The time To is transmitted to the body CPU 5. By transmitting the expected drive time Tc or the release return drive time To to the body CPU 5, the release time lag can be optimized.

  The present invention is not limited to the above-described embodiment, and can be variously modified within the scope of the present invention.

  For example, in the above-described embodiment, a single-lens reflex digital still camera has been described. However, the camera of the present embodiment may be a silver salt camera or a video camera. It can also be applied to cameras for small devices such as mobile phones.

FIG. 1 is a block diagram of a camera system having a lens barrel provided with an aperture driving device according to an embodiment of the present invention. FIG. 2 is a flowchart of the diaphragm operation in the diaphragm driver according to the embodiment of the present invention. FIG. 3 is a flowchart of the opening operation in the aperture driving device according to the embodiment of the present invention. FIG. 4 is a flowchart of the retry operation in the aperture driving device according to the embodiment of the present invention. FIG. 5 is a schematic diagram showing the relationship among the open position, open standby position, and target stop position of the stop mechanism shown in FIG. FIG. 6 is a graph showing position detection at the open position.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Camera body 2 ... Lens barrel 3 ... Power supply 5 ... Body CPU
9-14 ... Contact 15 ... Lens CPU
16 ... Non-volatile memory 17 ... Aperture setting unit 22 ... Switch 23 ... Aperture switch 25 ... Position detection sensor 26 ... Aperture mechanism 26a ... Aperture blade

Claims (8)

An adjustable area of the opening through which light passes, and the opening is movable between a position narrowing from the open waiting position at a predetermined, and, with the open standby position to the predetermined narrowing position In between, the throttle mechanism in which the open position exists on the side closer to the open standby position than the predetermined throttle position ,
A drive unit that drives the opening of the aperture mechanism;
A position detection sensor for detecting that the said opening passes through the opening position,
A narrowing drive signal for driving the opening is output to the driving unit, and the position detection sensor detects that the opening passes through the open position during driving by the driving unit. , the opening corresponding to the driving amount for moving to the target throttle position from the open position, and a control unit for outputting the narrowing drive signal for moving the opening to the target throttle position from the open position Have
The drive unit starts driving the opening from the open standby position, and after the position detection sensor detects that the opening passes through the open position, the drive unit Receiving the aperture drive signal for moving from the open position to the target aperture position from the control unit;
When the position detection sensor detects that the opening passes through the open position, the control unit determines in advance the narrowing drive signal counted from the open standby position to the open position. An aperture driving apparatus that corrects the aperture driving signal for moving the opening from the open position to the target aperture position when the aperture is not within the specified range . The control unit outputs an opening driving signal for driving the opening from the target aperture position, and the opening passes through the opening position by the position detection sensor during driving by the driving unit. The opening drive for moving the opening from the open position to the open stand-by position according to the drive amount for moving the opening from the open position to the open stand-by position is detected. The aperture driving device according to claim 1, which outputs a signal . The drive unit starts driving the opening from the target aperture position and detects the passage of the opening through the open position by the position detection sensor. The aperture driving device according to claim 2, wherein the opening driving signal for moving from the opening position to the opening standby position is received from the control unit . The controller determines in advance the opening drive signal counted from the target aperture position to the opening position when the position detection sensor detects that the opening passes through the opening position. 4. The diaphragm drive device according to claim 3, wherein the diaphragm drive signal for moving the opening from the open position to the open standby position is corrected when it is not within the specified range . When the opening drive signal sufficient to move the aperture of the aperture mechanism from the target aperture position to the open standby position is input from the control unit to the drive unit, the position detection sensor when the opening that passes through the opening position is not detected Te again, the drive enough the open drive signal to move from the target throttle position to the open waiting position from the control unit The diaphragm drive device according to claim 2, further comprising retry means for outputting to the unit. Comparing the actual narrowing drive signal required to move, the actual open drive signal required to move from the target throttle position to the open position the opening to the target throttle position from the open position and it calculates the differences, if the difference exceeds a predetermined range, the diaphragm driving device according to any one of claims 1 to 5, further comprising a warning means for outputting a warning signal. A lens barrel having a diaphragm driving device according to any one of claims 1-6. Claim 7 having a drive time expected means for transmitting to said camera body expected driving time for moving said opening from receiving a signal indicating a narrowing execution instruction from the camera body to actually the target throttle position Lens barrel.

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