JPH08890U - Moving lens barrel drive for variable focus camera - Google Patents

Abstract

(57) [Abstract] [Problem] To issue an alarm when an abnormal situation occurs in which a movable focal length is stopped by an obstacle while being driven in a retracted direction and a planned focal length position cannot be reached. At the same time, try to restore the normal condition immediately. SOLUTION: A T / W switch 4 is turned on, and while a lens barrel 12 is driven in a direction in which the lens barrel 12 is retracted from a T position to a W position, foreign matter such as a finger 15 and dust 16 is removed. It is assumed that the drive is stopped halfway between the outer peripheral surface and the camera body 17. Then, the control unit 10 recognizes that the timer 10 has exceeded the scheduled time and that the W position detection switch 5 as the moving lens barrel state detection means remains in the off state, and the motor drive circuit 11 is notified. An L-level T / W signal and an H-level motor ON / OFF signal are applied to drive the motor 1 and the lens barrel 12 is moved in the backward direction. At this time, the control unit 10 gives a command to the alarm means to generate an alarm.

Description

[Detailed description of the device]

[0001]

[Technical field to which the device belongs]

 The present invention relates to a varifocal camera, and more specifically, to a first focal length side located in a direction in which a movable lens barrel that houses and supports at least a part of a lens group forming a varifocal optical system is extended from a camera body. Driving a movable lens barrel in a variable focus camera having a focal length changing mechanism that changes a focal length by driving a motor between a position and a second focal length side position located in a direction in which the camera body is retracted. It is related to the device.

[0002]

[Prior art]

 Recently, bifocal cameras with a lens shutter are appearing one after another. That is, this type of camera generally has a main lens and a converter lens built into the camera body, and the main lens is always arranged so as to be movable along the photographing optical axis. It is configured to be inserted into the photographing optical axis. A focal length switching mechanism in such a multifocal camera is disclosed in, for example, Japanese Patent Laid-Open No. 59-17540.

In the varifocal optical system of this multifocal camera, the motor is actuated by the operation of the changeover switch for changing the focal length, the main lens is moved on the photographing optical axis, and the converter lens is selectively moved in the photographing optical axis. Is configured to be inserted into. In general, in order to move the main lens on the photographing optical axis to switch the focal length, a movable lens barrel that houses and supports the main lens is extended from the camera body or retracted into the camera body. However, when the movable lens barrel is extended into the camera body from the extended state, dust is caught in the gap between the movable lens barrel and the camera body, and the operator's (photographer's) finger is careless. If they are placed, these will become obstacles that will cause the movable lens barrel to stop in the middle of its operation, and it will not be possible to reach the prescribed position.

In recent years, not only the above-mentioned bifocal cameras but also varifocal type cameras have become electronic, and the moving lens barrel is driven by a motor through a mechanical unit to keep a predetermined focal distance. The position of the lens is confirmed by a lens position detecting switch or the like provided at the corresponding stop position, and the microcomputer for determining or controlling these positions is a so-called microcomputer. As described above, if the movable lens barrel becomes stuck while it is being retracted, the position detection switch does not change and the microcomputer determines that it has not reached the final stop position. It will continue to rotate.

Therefore, an excessive load is applied to the gear system of the above-mentioned mechanism section, which is not only dangerous because it is damaged or an operator's fingers are pinched and injured, but also the movable lens barrel is retracted. There was a big problem that shooting could not be done because the operation did not end. Another problem is that a large current flows through the motor and the power battery is wasted.

Therefore, in order to solve these problems, in the case where the position detection switch does not change even after a lapse of a predetermined time from the activation of the focal length changing operation (direction in which the moving lens barrel is retracted). It is known that the motor is configured to cut off the power supply when something abnormal happens, but such a structure has a problem that dust or a finger is caught in the gap between the moving lens barrel and the camera body. When the pinch is sandwiched, the motor stops in that state, and in order to remove these dust and fingers, the mechanism and the motor must be driven in reverse from the side of the movable lens barrel. However, depending on the structure of the mechanism part, there are some devices that cannot be driven from the opposite side, and even if it is possible, a strong external force is required, and in practice these dust and fingers cannot be taken out. There was a problem that there were many.

Further, in such a configuration, since the motor is simply de-energized after a predetermined time, even if the moving operation of the focal length is restarted, the movable lens barrel cannot move again. Regardless, it will drive the motor further in the direction that this is taken in, and it will not be possible to escape from the state where movement cannot be taken. Then, there was a defect that the shutter change was missed.

[0008]

[Problems to be solved by the device]

 The present invention has been made in view of the above circumstances, and an object thereof is to provide a movable lens barrel with a low cost and a simple structure toward the second focal length side. Even if an abnormal situation occurs in which the movable lens barrel cannot reach the planned position on the second focal length side due to dust or an obstacle such as an operator's finger, the abnormal situation is notified and Another object of the present invention is to provide a movable lens barrel drive device for a variable focus camera that can avoid damage to the above and can immediately recover from the abnormal situation by recovering to a normal state.

[0009]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention is directed to a first focal length side in which a movable lens barrel that houses and supports at least a part of a lens group that constitutes a variable focus optical system is located in a direction in which it is extended from a camera body. A variable focus camera having a focal length changing mechanism that changes a focal length by driving a motor between a position and a second focal length side position located in a direction in which the camera body is retracted. A focal length changing starter for starting a focal length changing operation for changing the distance, and a drive to the first focal length side or the second focal length side by receiving the output of the focal length changing starter. Whether the driving direction determining means for outputting the direction information indicating the driving direction and the movable lens barrel have moved by the predetermined amount between the first focal length side position and the second focal length side position. Detect whether A moving lens barrel state detecting means, a time measuring means for measuring a scheduled change time corresponding to a time required and sufficient for changing the focal length, and outputting a timing end signal when the scheduled change time elapses, and the moving lens barrel. Is set at a predetermined position, the motor driving means for driving and controlling the motor, and the direction information for driving to the second focal length side position are received from the driving direction determining means, and the motor driving means causes the movable lens barrel to move. The movable lens barrel has not reached the intended focal length position at the time of receiving the timing completion signal from the timing means, which starts the timing operation from the time when the driving is started toward the second focal length side position. When this is recognized by the detection signal output from the moving lens barrel state detecting means, the control means for controlling the motor driving means returns the moving lens barrel to the first focal length side. That has been made is characterized in.

[0010]

[Action]

 In the movable lens barrel driving device of the variable focus camera configured as described above, foreign matter such as an operator's finger or dust is in contact with or located on the outer periphery of the lens barrel, so that these foreign matter may be separated from the camera body. If an abnormal situation occurs in which a pinch between the two causes the lens barrel to stop, the following actions are taken. The above operation is performed when a time-completion signal is received after a predetermined time has elapsed from the time-measuring means that started the time-measuring operation from the time when the movable-lens barrel was started to be driven toward the second focal length by operating the focal-length changing activation means. When the control means recognizes that the movable lens barrel has not reached the planned focal length position by the detection signal output from the movable lens barrel state detection means, the control means judges the above-mentioned abnormal situation and issues a warning to the warning means. The motor driving means is controlled so as to issue a command to emit the light and return the movable lens barrel to the first focal length side.

On the other hand, when the movable lens barrel reaches the predetermined position before the scheduled time set in the time measuring means has elapsed since the focal length changing operation was activated, the control means causes the movable lens barrel state detection means. It is not recognized as abnormal depending on the detection signal output from the above, and the above warning and the operation of returning the movable lens barrel to the first focal length side are not performed.

[0012]

[Embodiment of device]

 Hereinafter, embodiments of the present invention will be specifically described with reference to the accompanying drawings. FIG. 1 is a block diagram showing the overall configuration of an embodiment of a movable lens barrel driving device for a variable focus camera according to the present invention, and FIGS. 2 to 4 are all diagrams showing the operation sequence of the embodiment of FIG. 2 is a main routine showing the entire focus changing operation, FIGS. 3 and 4 are subroutines used in the main routine shown in FIG. 2, and FIG. The operation, FIG. 4, likewise shows the feeding operation of the movable lens barrel.

In FIG. 1, reference numeral 1 is an externally operable release switch composed of a mechanical switch for starting a photographing operation of a camera, 2a and 2b are pull-up resistors, and 3 and 4 are focal length changing start for changing a focal length, respectively. T / W switch consisting of a pull-up resistor and a mechanical momentary switch that can be operated externally, D1 and D2 are short-circuit preventing diodes, and 5 to 8 are movable lens barrel state detecting means. Of these, 5 is a W position detection switch composed of electrical contacts for detecting a position on the short focal length side as the second focal length side position (hereinafter referred to as “W position”), and 6 is a first position detection switch. Is a T position detection switch including an electric contact for detecting a position on the long focal length side (hereinafter, referred to as "T position") as a position on the focal length side.

Both 7 and 8 are pull-up resistors. Reference numeral 9 denotes a pull-up control circuit 9. The pull-up control circuit 9 has a pull-up control transistor 9a, a bias resistor 9b connected between the base and the emitter of the pull-up control transistor 9a, and a base of the pull-up control transistor 9a. It is composed of base resistors 9c connected in series. Reference numeral 10 denotes a control unit (hereinafter referred to as "CPU") as a control unit having a timer TM as a timing unit and a direction flag FG as a driving direction determination unit.

In this CPU 10, CM1 and CM2 are control output terminals for outputting a motor ON / OFF signal (r) and a T / W signal (q), respectively, and INT0 is a control output terminal of the CPU 10 when an applied signal becomes L level. The interrupt input terminals for starting the interrupt operation, RL and T / W, are identification input terminals for identifying the interrupt source of the interrupt operation, and the release switch 1 and the T / W switch 4 are closed. The interrupt source is recognized when it goes to L level at this time. CTL is a control output terminal that holds an H level when not operating and outputs an L level signal when the pull-up control circuit 9 is in an operating state. TWW and TWT are both input terminals.

Reference numeral 11 is a motor drive circuit as a motor drive means, and 12 is a movable lens barrel (hereinafter, simply referred to as “lens barrel”) 12 a for accommodating and supporting a main lens system as a lens system that moves with a change in focal length. Is a flange portion provided at the front end of the lens barrel 12, 12b is an arm portion that drives the lens barrel 12 through a mechanism unit (not shown), and 13 is the lens barrel 12 through the mechanism unit (not shown). A motor that drives over the range of the T position and the W position (direction is indicated by an arrow), 14 is a motor power source to be supplied to the motor 13 via the motor drive circuit 11, and 15 is a camera operator, for example. Fingers, 16 are dust as foreign matter, and 17 is a camera main body partly omitted.

The alternate long and short dash line is the optical axis. The internal timer TM of the CPU 10 has a predetermined time, which is at least longer than the moving time required for the lens barrel 12 to move from the planned focal length position, eg, the T position to the W position. For example, the moving time is 0.7 seconds. If so, it is set to about 1.5 to 2 seconds, that is, the scheduled change time corresponding to the time required and sufficient for changing the focal length.

Explaining the connection relationship here, one end of each of the pull-up resistors 2a, 2b, 3 is connected in parallel to the pull-up power source + V and the emitter of the pull-up control transistor 9a, respectively, and the pull-up resistor 2a The other end is connected to one end of the release switch 1 and the T / W switch 4 through forward blocking diodes D1 and D2, respectively, and to the interrupt input terminal INT0, and the other end of the pull-up resistor 2b is It is directly connected to one end of the release switch 1 and connected to the identification input terminal RL and the cathode side of the diode D1, and the other end of the pull-up resistor 3 is directly connected to one end of the T / W switch and the identification input terminal. T / W is connected to the cathode side of diode D2, and the other ends of T / W switch 4 and release switch 1 are grounded. Have been.

Both ends of the pull-up resistors 7 and 8 are connected to the collector of the pull-up control transistor 9 a, and the other ends thereof are connected to one ends of the W position detection switch 5 and the T position detection switch 6, respectively. It is connected to input terminals TWW and TWT, and the other ends of both switches 5 and 6 are both grounded. The base of the pull-up control transistor 9a is connected to the control output terminal CTL via the base resistor 9c. The instruction output terminals CM1 and CM2 are connected to the control input terminals ON / OFF and T / W of the motor drive circuit 11, respectively.

The motor drive circuit 11 stops the motor when the motor ON / OFF signal (r) input to the instruction input terminal ON / OFF is at the L level, rotates the motor when the motor is at the H level, and turns on the T / T signal. When the W signal (q) is at the L level, the lens barrel 12 is driven in the direction to be extended from the W position toward the T position, and when it is at the H level, is driven in the direction to be extended from the T position to the W position. As described above, the motor power supply 14 is connected to the motor 13. The W position detection switch 5 and the T position detection switch 6 are closed when the lens barrel 12 reaches a predetermined focal length position, for example, the W position and the T position, and an L level signal as a detection signal is output. It is configured to output.

The focus switching mechanism in the camera of this embodiment will be described. The main lens system housed and supported in the lens barrel 12 is always arranged on the photographing optical axis and can slide along the photographing optical axis. Is configured. Then, a converter lens system (not shown) is inserted on the photographing optical axis in the state of the T position and set at a position near the film aperture surface. Further, in the state of the W position, the converter lens system is configured to be retracted from the photographing optical axis.

In the initial state, the lens barrel 12 and the converter lens system are arranged in the W position. Therefore, at this time, the direction flag FG in the CPU 10 also holds the state set at the W position as the direction information. 2 to 4 will be described in detail later in the description of the operation, and will be omitted here. The flowchart of FIG. 2 is started when the signal input to the interrupt input terminal INT0 of FIG. 1 becomes L level.

Next, the operation of the present embodiment configured as described above will be described with reference to the flow charts of FIGS. Now, it is assumed that the apparatus is in the initial state, and therefore the lens barrel 12 is at the second focal length side position (W position). Here, when the T / W switch 4 is closed, the signal at the interrupt input terminal INT0 of the CPU 10 becomes L level. At this point, the CPU 10 starts the main routine showing the focus changing operation shown in FIG. 2 from START. First, the CPU 10 lowers the control output terminal CTL to L level, which turns on the pull-up control transistor 9a, and the input terminals TW W and TWT of the CPU 10 are pulled up via pull-up resistors 7 and 8, respectively. Be done.

That is, the CPU 10 is ready to read the signal levels of the both input terminals TWW and TWT. Next, in the conditional branch "T / W switch?", It is checked which of the identification input terminal RL and T / W is at the L level. In this case, since the T / W switch 4 is closed and the identification input terminal T / W is at the L level, it is recognized that the interrupt source was the T / W switch 4, and the process branches to YES. To do. In this example, the condition branch is NO when the release switch 1 is closed and a predetermined photographing operation is performed.

Now, in the next "W position?", The internal direction flag FG is checked. The direction flag FG indicates the W position because it is the initial state. Therefore, the flow branches to YES and proceeds to the next subroutine "W → T switching". The contents of this subroutine are shown in FIG.

Turning to FIG. 4, in the “lens barrel extension”, the CPU 10 sets the T / W signal (q) of the control output terminal CM 2 to the L level, and the motor drive circuit 11 extends the barrel (T position direction). ), The motor ON / OFF (r) of the control output terminal CM2 is raised to the H level, and the motor 13 is rotated in the T position direction. Then, the lens barrel 12 starts moving leftward in FIG. At the next "timer start", the internal timer TM is cleared to zero and then the clock operation is started. In the next conditional branch "T position?", The signal level of the input terminal TWT is checked. The lens barrel 12 has not yet reached the T position because it has just started moving, and therefore the T position detection switch 6 is in the state (open) shown in FIG. 1 and therefore branches to NO.

In the next “within set time?”, It is checked whether the timer TM has exceeded a preset set time (scheduled switching time), for example, 2 seconds. In this case as well, since the operation has just started, the flow branches to YES, returns to "T position?", And repeats the above operation. This operation loop will be referred to as a “feed check loop”. After that, when the lens barrel 12 reaches the T position, the T position detection switch 6 is closed, and the "T position?" In the feeding check loop is branched to YES to escape from the feeding check loop. At the next "motor stop", the motor ON / OFF signal (r) is lowered to the L level to stop the motor 13, the direction flag FG is updated to the T position, and the feeding operation is completed. Then, at the final RTS, it returns to the main routine of FIG.

Now, moving to FIG. 2, the CPU 10 raises the signal of the control output terminal CTL to the H level by “CTL output OFF”, turns off the pull-up control circuit 9, and enters the sleep state. At this time, the lens barrel 12 is in the state shown in FIG. Next, a case will be described in which an abnormal situation occurs due to, for example, the operator's finger 15 or dust 16 being in contact with or positioned on the outer circumference of the lens barrel 12 as shown in FIG. When the T / W switch 4 is closed in this state, the flow chart of FIG. 2 is the same operation from START to the conditional branch “W position?” As described above. In this conditional branch, the direction flag FG is Since it has been updated to the T position, the routine branches to NO and proceeds to the subroutine "T → W switching".

Now, moving to the flowchart of the subroutine shown in FIG. 3, first, in "lens barrel retraction", the CPU 10 sets the T / W signal (q) to the H level and the motor ON / OFF signal (r) to the H level. And the motor 13 is rotated in the take-in direction. The lens barrel 12 starts moving rightward in FIG. In the next "timer start", the internal timer TM is cleared to zero as described above, and then the time counting operation is started. At the next "W position?", The signal level of the input terminal TWW is checked, and since the operation has just started, the W position detection switch 5 is opened and the flow branches to NO.

Similarly, since the next “within set time?” Has not yet passed much time, the flow branches to YES, returns to “W position?” Again, and repeats the same operation. Here, this operation loop will be referred to as a "convolution check loop". After that, when the lens barrel 12 reaches the W position, it branches to YES in the "W position?" In the above-mentioned feed-in check loop and exits from the feed-in check loop, and then the feed-out explained in FIG. In the same manner as the operation, the resting state is reached. In this case, an obstacle such as the finger 15 or the dust 16 is caught between the camera body 17 and the flange portion 12a, or the camera body 17 and the outer circumference of the lens barrel 12 are separated from each other. When the lens barrel 12 is caught in the sliding gap, the lens barrel 12 is locked at a position before reaching the W position, and an abnormal situation occurs in which the lens barrel 12 cannot move.

Therefore, there is no escape from the renormalization check loop by branching from “W position?” In the renormalization check loop to YES. However, in the present embodiment, when the scheduled switching time of 2 seconds elapses, the flow branches to NO at “within set time?” In the above-mentioned check-in loop and exits the above-mentioned check-in loop. Then, the process proceeds to the next subroutine “W → T switching”, and the process then proceeds to the subroutine flowchart shown in FIG. Since the operation content of FIG. 4 has already been described, the correspondence with the flow chart is omitted, but the CPU 10 recognizes that there is an abnormal situation and immediately reverses the motor 13 in the direction to extend the lens barrel 12 to the T position side. Then, the timer T M is started to reach the feeding check loop.

If the lens barrel 12 can reach the T position, the same operation as described above is performed, and the rest state is finally reached. However, when the finger 15 and the dust 16 are pushed out to the T position side to the extent that the fingers 15 and 16 can be removed, a new obstacle (Fig. If (not shown) appears and the T position cannot be reached, there is a possibility that escape from the “T position?” In the feeding check loop will disappear, but the conditional branch of “within the set time?” At 2 seconds, the motor 13 is immediately stopped by the "motor stop" and the feeding operation is completed.

Here, for example, if a warning means is provided to warn the photographer that the lens barrel 12 is not stopped at the proper position, the photographer can recognize the obstacle and detect an obstacle. After the removal, the T / W switch 4 is turned on again to set the regular W position according to the flowcharts shown in FIGS. 2 and 3. Therefore, after this, if the release switch 1 is closed, the above-mentioned photographing operation can be freely started.

As described above, according to the present embodiment, when the lens barrel 12 cannot reach the W position within a predetermined time for some reason in the retraction operation for driving the lens barrel 12 to the W position, Since the lens barrel 12 is immediately extended to the T position side in order to deal with an abnormal situation, even if the finger 15 and the dust 16 are caught between the camera body 17 and the lens barrel 12, the lens barrel 12 is immediately released. This has the advantage that it can avoid or minimize damage to the human body such as fingers, and also has the advantage that dust 16 can be easily removed. It is possible to limit the period of time during which a large amount of current is passed, and therefore not only do not apply an excessive load to the gear system of the mechanism, but also have the advantage of maintaining a good condition, and quickly escape from an abnormal situation. Since there is a transition to a state in which the shooting operation can be activated, there is an advantage that the photo opportunity can be maximized.

Further, even in the feeding operation for dealing with the above-mentioned abnormal situation, the motor 13 is stopped in response to the occurrence of a new abnormal situation, that is, since it has a double safety function, it is possible to leave once. There is an advantage that the finger 15 and the dust 16 in the state are not pinched again, and the adverse effects on the motor 13 and the gear system are prevented. Further, even when the part of the mechanism part that operates in the retracting direction is damaged, the CPU 11 detects an abnormal situation and immediately advances the lens barrel 12 to the T position, so that it is possible to continue shooting and miss a shutter chance. There is an advantage that it can be prevented.

The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. For example, the setting time of the timer TM is not limited to 1.5 to 2 seconds, and any time may be set as long as the above-mentioned moving time is set to an appropriate time in consideration of the discharge capacity and cold resistance of the battery. .

Further, the driving direction determination means is not limited to the direction flag FG and may be performed by recognizing the states of the W position detection switch 5 and the T position detection switch 6. In this case, there is an advantage that the direction flag FG can be omitted. Further, the T / W switch 4 is not limited to a single throw type switch having only two states of ON / OFF, and a so-called seesaw switch having four states may be used.

[0038]

[Effect of device]

 As described above in detail, according to the present invention, when the movable lens barrel is driven in the direction in which the movable lens barrel is retracted toward the second focal length side, dust or obstacles such as a photographer's finger are generated in the movable lens barrel. If an abnormal situation occurs in which the movable lens barrel cannot reach the planned position on the side of the second focal length due to being sandwiched between the camera body and the camera body, the operator is warned of the abnormality and the body such as the finger or the like. To provide a movable lens barrel drive device for a variable focus camera, which can avoid or minimize damage to the camera and can immediately recover from the above abnormal condition and return to a state where normal optical performance is exhibited. You can

[Brief description of drawings]

FIG. 1 is a block diagram showing an overall configuration of an embodiment of a movable lens barrel driving device of a variable focus camera according to the present invention.

FIG. 2 is a flowchart showing an operation sequence of the embodiment shown in FIG. 1 and is a main routine showing an entire focus changing operation.

FIG. 3 is a subroutine used in the main routine of the embodiment shown in FIG. 2, and in the case of this figure, it shows the retracting operation of the movable lens barrel.

FIG. 4 is a subroutine used in the main routine of the embodiment shown in FIG. 2, and in the case of this figure, it shows the moving-out operation of the movable lens barrel. 1 release switch, 4 T / W switch, 5 W position detection switch, 6 T position detection switch, 9 pull-up control circuit, 10 control unit (CPU), TM timer, FG direction flag, CM1, CM2 control output terminal, INT0 Interrupt input terminal, RL, T / W identification input terminal, CTL control output terminal, TWW, TWT input terminal, 11 motor drive circuit, 12 moving lens barrel (lens barrel), 12a flange part, 13 motor, 14 motor power supply, 15 Fingers, 16 dust, 17 camera body.

Claims (1)

[Scope of utility model registration request] 1. A first focal length side position which is located in a direction in which a movable lens barrel that houses and supports at least a part of a lens group that constitutes a variable focus optical system is extended from the camera body, and the movable lens barrel is retracted into the camera body. In a varifocal camera having a focal length changing mechanism for changing the focal length by driving with a motor between the second focal length side position located in the direction where the focal length is changed, the focal length changing operation for changing the focal length is started. And a direction information for instructing a driving direction of whether to drive to the first focal length side or the second focal length side in response to the output of the focal length change starting unit. Drive direction determination means, and moving lens barrel state detection means for detecting whether or not the movable lens barrel has moved a predetermined amount between the first focal length side position and the second focal length side position, Above focus Timing means for measuring a scheduled change time corresponding to a sufficient time necessary for changing the distance and outputting a timing end signal when the scheduled change time elapses, and the motor for setting the movable lens barrel at the scheduled position. The motor driving means for controlling the driving and the direction information for driving to the second focal length side position are received from the driving direction determining means, and the motor driving means directs the movable lens barrel to the second focal length side position. It is output from the moving lens barrel state detecting means that the moving lens barrel has not reached the planned focal length position at the time of receiving the timing completion signal from the time measuring means which has started the time counting operation from the time when the driving is started. And a control means for controlling the motor driving means so as to return the movable lens barrel to the first focal length side when recognized by the detected signal. La movable lens barrel drive unit.