JP3893189B2 - Lens barrel and optical apparatus using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a lens barrel and an optical apparatus using the lens barrel, and is particularly suitable for a television photographing lens used for television photography or the like.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a television photographing lens (photographing lens) used in television photography or the like has a plurality of lens groups driven in the optical axis direction by a manual or motor (electric) for zooming or focusing. Among these, when the lens group is driven by a motor, position detection means for detecting the position of the lens group on the optical axis is provided, and the motor is controlled to move the lens group to the command position.
[0003]
FIG. 4 is a cross-sectional view of a main part of a lens barrel in which a part of a lens group of a conventional photographing lens is driven.
[0004]
In the figure, reference numeral 34 denotes a moving lens group, which is supported by a lens holding cylinder 35 and can be displaced in the optical axis direction with respect to the fixed barrel 36. Reference numeral 37 denotes a lens driving ring, which is rotationally driven by a motor 40 via a first gear 38 and a second gear 39. The lens driving ring 37 and the lens holding cylinder 35 are connected by a connecting pin 41, and the lens group 34 is displaced in the optical axis direction by the driving force from the motor 40. An encoder 42 is fixedly disposed on the fixed barrel 36, and the rotational movement amount of the lens driving ring 37 is detected according to the rotation of the encoder slit 43 attached to the inner periphery of the lens driving ring 37. A resistor 44 is annularly attached to the inner periphery of the lens drive ring 37 and is in contact with the brush 45 fixed to the fixed barrel 36. The resistor 44 and the brush 45 serve as a switch for detecting the lens operation end.
[0005]
In the lens barrel having such a configuration, in order to drive and control the lens group 34 with the motor 40, it is necessary to first perform the initial setting by moving the lens group 34 to the origin position (also referred to as an operation end or an end). is there. Conventionally, the lens group 34 is driven in a predetermined direction when the apparatus is turned on, and the operating end of the lens group 34 is recognized by the electrical switches (44, 45) as described above. Initial settings were made to be the origin for drive control.
[0006]
[Problems to be solved by the invention]
In a lens barrel having a function of performing an initial setting by moving a conventional lens group to an origin position, a movement amount detection device (encoder) for detecting a relative movement amount of the lens group, and an initial position of the lens group Two detection means for operating end detection switches (resistors and brushes) necessary for the conversion are arranged.
[0007]
In general, providing such two detection means in a lens barrel not only hinders downsizing of the lens barrel but also increases costs. As a countermeasure against such a problem, there is a method of providing one detection means for detecting the absolute position of the lens group.
[0008]
As this detection means, for example, there is an absolute encoder, but this tends to increase the size of the entire apparatus. The potentiometer has no problem in performing analog control, but has a problem that sufficient resolution cannot be obtained for high-precision digital control. As another countermeasure, when the operating end detection switch is eliminated and the position of the lens group is initialized, the lens group is driven to the end point on the mechanism, and the position where the lens movement is restricted is set as the origin position. There is also a way to recognize it. However, this method has a problem that the power transmission mechanism and the motor itself are damaged by an impact when the lens group reaches the end point on the mechanism.
[0009]
According to the present invention, by appropriately setting a driving mechanism for driving and controlling the lens group, a predetermined lens group among the lens groups constituting the photographing lens is moved to an operating end (mechanical end) that is an end portion of a first predetermined range. After driving, the lens group is driven to the servo end (servo origin) which is the end of the second predetermined range where the servo control is performed inside the mechanical end, and the lens group can be driven and controlled with high accuracy and stability. It is an object of the present invention to provide a lens barrel and an optical device using the same.
[0010]
In addition, the present invention provides a load limiting means appropriately set in the driving force transmission path when a predetermined lens group among the lens groups constituting the photographing lens is driven to the operating end (end). A lens mirror that can be driven accurately and stably while mitigating impact generated when the group is driven to the operating end of the mechanism with the load limiting means and preventing damage to the motor and power transmission unit An object is to provide a tube and an optical device using the tube.
[0011]
The present invention also provides a differential mechanism for manual and electric switching including a load limiting means in the driving force transmission path when moving a predetermined lens group constituting the photographing lens, and the lens group is mounted on the mechanism. By removing the impact generated when driven to the operating end by the differential mechanism, the lens group can be accurately placed at the origin position without providing a separate load limiting means and without using a conventional switch for detecting the operating end. It is an object of the present invention to provide a lens barrel that can be driven and controlled and an optical device using the same.
[0012]
[Means for Solving the Problems]
  The lens barrel of the invention of claim 1 comprises:
    Driving means for driving the lens;
  A power transmission system for transmitting the driving force of the driving means to the lens;
  Mechanical movement of the lensendPlaced inStopper memberWhen,
A differential mechanism for alleviating an impact applied to the power transmission system by a sliding mechanism provided in the power transmission system when the movement of the lens is mechanically stopped by the stopper member;
  Relative position detecting means for detecting the relative position of the lens;
When the power is turned on, the lens is driven toward the mechanical end, and it is detected that the lens is at the mechanical end based on the driving signal of the driving unit and the detection result of the relative position detecting unit. And a control means for driving the lens to an electrical end set inside the mechanical end.
[0013]
  According to a second aspect of the invention, in the first aspect of the invention, the control means determines the electrical end of the lens based on movement information stored in advance in the storage means.
[0014]
  According to a third aspect of the present invention, in the second aspect of the present invention, the lens barrel includes a temperature detection unit, and the control unit selects movement information stored in the storage unit based on a detection result of the temperature detection unit. It is characterized by doing.
[0015]
    A lens barrel according to a fourth aspect of the invention comprises a driving means for driving a lens;
  A power transmission system for transmitting the driving force of the driving means to the lens;
  Mechanical movement of the lensendPlaced inStopper memberWhen,
A differential mechanism for alleviating an impact applied to the power transmission system by a sliding mechanism provided in the power transmission system when the movement of the lens is mechanically stopped by the stopper member;
  Relative position detecting means for detecting the relative position of the lens;
When the power is turned on, the lens is driven toward the mechanical end, and it is detected that the lens is at the mechanical end based on the drive signal of the drive means and the detection result of the relative position detection means. And, after detecting the positions of both ends of the mechanical end, control means for driving and controlling the lens within the range of the electrical end set inside the mechanical end. .
[0016]
  According to a fifth aspect of the invention, in the fourth aspect of the invention, the control means determines the electrical end of the lens based on movement information stored in advance in the storage means.
[0017]
  According to a sixth aspect of the present invention, in the fifth aspect of the present invention, the lens barrel includes a temperature detection unit, and the control unit selects movement information stored in the storage unit based on a detection result of the temperature detection unit. It is characterized by doing.
[0018]
  According to a seventh aspect of the present invention, in the fourth aspect of the present invention, the control means compares the distance between both ends of the mechanical end with a preset reference distance, and again determines the mechanical end based on the comparison result. It is characterized by performing detection.
[0019]
  An optical apparatus according to an eighth aspect of the invention is characterized by using the lens barrel according to any one of the first to seventh aspects.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a cross-sectional view of an essential part of Embodiment 1 of the present invention. In the present embodiment, a part of a lens barrel that can be driven by switching between electric and manual operation without a changeover switch when the optical means (lens group) 1 held in the housing is driven is shown.
[0026]
In FIG. 1, 1 is a movable lens group (optical means), 2 is a lens holding frame, and holds the lens group 1. The lens holding frame 2 is engaged with a fixed barrel 3 constituting a main body of the lens barrel with a screw and is movable in the optical axis direction. Reference numeral 4 denotes a manual ring (manual operation means) for rotating the lens group 1 when it is manually operated. Reference numeral 5 denotes an ultrasonic motor as drive means, which is a drive means for electrically driving the lens group 1 using vibration waves.
[0027]
The ultrasonic motor 5 includes a ring-shaped stator 5a that emits vibration waves and a rotor 5b, and a piezoelectric element (PZT) fixed to the end face of the stator 5a generates vibration. A slit (not shown) is provided in the radial direction at the tip of the stator 5a, and a stator rotation preventing member 6 is disposed in the slit to prevent the stator 5a from rotating. An annular felt 8a fixed to the felt fixing ring 7 is disposed on the other end face of the stator 5a. Further, a disc spring 9 is provided on the side surface of the felt fixing ring 7. The stator 5a is pressed in the direction of the rotor 5b with a predetermined force by a disc spring pressing member 11 that meshes with the disc spring 9, the motor base 10, and a screw.
[0028]
The stator rotation preventing member 6 is fixed to the motor base 10 by a stator rotation preventing member fixing ring 12. When a predetermined voltage is applied to the PZT of the stator 5a under such a configuration, the rotor 5b is rotated by a vibration wave generated at the tip of the stator 5a. On the other hand, the rotor output ring 13 is fixed to the side surface of the rotor 5b via a vibration isolating rubber 14, and rotates integrally with the rotor 5b.
[0029]
A roller member (rolling member) 15 rotates around its own axis and can roll in the circumferential direction of the fixed barrel 3. The roller member 15 is in contact with both end faces of the annular ball race outer ring 16 fixed to the manual ring 4 and the rotor output ring 13 and at the same time is rotatable about pins 18 protruding from the ball race inner ring 17 as its own axis. . At least three roller members 15 are arranged with the optical axis being concentric.
[0030]
In this embodiment, the roller member 15, the rotor output ring 13, and the ball race outer ring 16 constitute one element of the load limiting means, and are provided in the power transmission path. At the time of overload, the contact surface between the roller member 15 and the rotor output ring 13 or the contact surface between the roller member 15 and the ball race outer ring 16 slips to eliminate the impact.
[0031]
Reference numeral 19 denotes a ball race output ring, which is fixed to the ball race inner ring 17 with a screw and rotates around the motor base 10 and at the same time constitutes a bearing together with the ball race outer ring 16, the ball race inner ring 17, and the sphere 20. Further, the end surface of the ball race outer ring 16 is in contact with a race support surface 10a provided on the motor base 10, and the entire bearing is pressed against the race support surface 10a by a disc spring 9 which is a pressurizing means of the ultrasonic motor 5. Yes.
[0032]
The bearing composed of the roller member 15, the ball races 16 and 17, and the sphere 20 constitutes an element of a differential mechanism that switches between lens driving manual and electric without a switch.
[0033]
Next, the function will be described. When the lens group 1 is driven electrically, the rotor 5b, the vibration isolating rubber 14, and the rotor output ring 13 are integrally rotated by the ultrasonic motor 5. When the rotational torque of the manual ring 4 is set to a predetermined value (about half of the lens driving torque) or more, the roller member 15 in contact with the rotor output ring 13 rotates around the pin 18 and at the same time the contact surface of the roller member 15 The generated friction causes the ball race inner ring 17 to rotate integrally around the optical axis. At this time, since the sliding torque of the manual ring 4 acts as a resistance force on the ball race outer ring 16, the ball race outer ring 16, that is, the manual ring 4 does not rotate. Further, the rotation angle of the ball race inner ring 17 is half of the rotation angle of the rotor 5b, but the transmission torque is about twice the output torque of the rotor 5b.
[0034]
A ball race output ring 19 is fixed to the ball race inner ring 17, and a lens driving ring 21 is integrally fixed to the tip of the ball race output ring 19. Thereby, the lens holding frame 2 is driven in the optical axis direction through the connecting pin 22 by the rotation of the lens driving ring 21. In this way, during electric driving, the driving force is not transmitted to the manual ring 4 on the outer periphery of the lens, and only the lens group 1 is driven without operating the manual ring 4.
[0035]
On the other hand, when the lens group 1 is driven manually, the ball race outer ring 16 fixed to the manual ring 4 first rotates as the manual ring 4 rotates. The manual operation torque at this time is set to be less than the holding torque of the ultrasonic motor 5 (friction torque between the rotor 5b and the stator 5a), and the roller member 15 in contact with the rotor output ring 13 rotates around the pin 18. The driving force is not transmitted to the driving means 5 side. As the ball race outer ring 16 rotates, the ball race inner ring 17 rotates integrally.
[0036]
At this time, the rotor output ring 13 is not rotated by the holding force of the ultrasonic motor 5. The ball race inner ring 17 rotates at a half rotation angle of the manual ring 4 and drives the lens group 1 via the ball race output ring 19, the lens drive ring 21, and the connecting pin 22. In this structure, the rotation range of the lens drive ring 21 is restricted by the stopper member 23, but the manual ring 4 is still rotatable after the lens group 1 reaches the operating end. Thus, by using the differential mechanism (elements 13 and 15 to 20) using the roller member 15, switching between electric and manual is realized without a changeover switch.
[0037]
  A scale 21 a is engraved on the outer peripheral surface of the lens driving ring 4, and an index line 10 b is engraved on the outer peripheral surface of the motor base 10. An optical value corresponding to the lens position is obtained from the transparent window 4 a provided on the manual ring 4. I have confirmed. Further, an encoder (movement information detecting means) 24 for detecting a movement amount is fixed to the fixed barrel 3, and the rotation of the lens driving ring 21 is rotated according to the rotation of the encoder slit 25 attached to the inner peripheral surface of the lens driving ring 21. The amount of movement is detected. In order to control the lens group 1 with a motor, it is indispensable to grasp the absolute position of the lens group 1. However, since the encoder 24 detects only the movement amount of the lens group 1, that is, the relative position information, the lens group 1 is ultrasonically detected. Before control by the motor 5, it is necessary to initialize the lens position by moving the lens group 1 to a predetermined origin position.
[0038]
In this embodiment, the lens position is initialized by the following means. First, before the lens group 1 is controlled by the motor 5, the lens group 1 is driven in a predetermined direction within a predetermined time, for example, when power is turned on from a power input means provided in the lens barrel. Since the operation range of the lens driving ring 21 is restricted by the stopper member 23, the lens group 1 stops at the operating end (mechanical end) and at the same time, the change in the output signal of the encoder 24 stops. If a state in which the output signal of the encoder 24 does not change is detected for a predetermined time despite the drive command being given to the ultrasonic motor 5, the end detection means (also referred to as end detection means) in the CPU is the lens. The operation end is determined, and the lens control position counter is cleared to be the control operation end.
[0039]
  When the lens driving ring 21 reaches the stopper member 23, an impact is given to the power transmission system, and at the same time, the motor 5 continues to be driven for a predetermined time after the lens is stopped.15A differential mechanism using the above acts as a torque limiter and absorbs this impact, and at the same time eliminates the overload condition. That is, if the frictional force generated between the roller member 15 constituting the load limiting means in the power transmission path between the ultrasonic motor 5 and the lens group 1 and the rotor output ring 13 is less than a predetermined value, the lens group From the point when 1 reaches the operating endConfigure the sliding mechanismSlip occurs between the roller member 15 and the rotor output ring 13.
[0040]
Even when the frictional force generated between the roller member 15 and the rotor output ring 13 is greater than or equal to a predetermined value, the manual ring 4 that has been stationary until the lens group 1 reaches the operating end rotates. Since the power generated by the motor 5 is switched from the lens driving ring 21 to the manual ring 4, no impact or overload is applied to the power transmission system or the motor itself even after the lens group 1 reaches the operating end.
[0041]
In the present embodiment, with the structure as described above, there is no need to provide a switch for detecting the operating end of the lens group, and there is no damage to the power transmission system or the motor itself. The position of the operation end is detected.
[0042]
2 and 3 are cross-sectional views of main parts of Embodiment 2 of the present invention. FIG. 2 shows a part of a photographing lens that can be driven by switching between electric and manual without a changeover switch when driving the lens group 1 in the housing.
[0043]
The present embodiment is different from the first embodiment in that a load limiting means using a magnetic force is used instead of a differential mechanism using a roller member as a load limiting means provided in a power transmission mechanism connecting the motor 5 and the moving lens group 1. It is in the place that adopted the differential mechanism. The structure and function will be described below.
[0044]
In FIG. 2, the same members as those in FIG. 1 are denoted by the same reference numerals, and description of the members is omitted. FIG. 3 is a partially enlarged view of FIG. 2 showing the structure of the differential mechanism using magnetic force. In the figure, reference numeral 26 denotes a ball race outer ring, which constitutes a bearing together with a ball race inner ring 27, a ball race presser ring 28 and a sphere 20 fixed to the motor base 10. Further, the rotor 5b of the ultrasonic motor 5 and the vibration isolating rubber 14 are integrally rotated around the optical axis. An annular steel plate 29 is fixed to the end surface of the ball race outer ring 26.
[0045]
On the other hand, an annular magnet 32 is fixed to an end face of a manual ring 30 that is rotated when the lens group is manually operated, with an annular yoke 31 interposed therebetween. A resin ring 33 is attached to the other end surface of the magnet 32 to prevent wear of the magnet end surface, and the yoke 31, the magnet 32, and the resin ring 33 rotate around the optical axis integrally with the manual ring 30. . Further, the end surface of the resin ring 33 is in contact with a steel plate 29 fixed to the ball race outer ring 26, whereby the manual ring 30 and the ball race outer ring 26 are magnetically coupled by the force of the magnet 32, and at the same time, the resin ring 33 and the steel plate are joined. The 29 contact surfaces 33a can be rotated as sliding surfaces.
[0046]
In order to realize a differential mechanism that switches between lens driving electric and manual using magnetic force, the friction torque of the contact surface 33a generated by the magnetic force of the magnet 32 is equal to or higher than the driving torque of the lens group 1 and the ultrasonic motor 5 is held. It is necessary to adjust below the torque. Here, the steel plate 29 and the resin ring 33 constitute load limiting means, and the steel plate 29, the yoke 31, the magnet 32 and the resin ring 33 constitute magnetic coupling means.
[0047]
When the lens group 1 is electrically driven based on such a configuration, the ball race outer ring 26 first rotates integrally with the rotor 5 b of the ultrasonic motor 5. Since the friction torque between the manual ring 30 and the ball race outer ring 26 is set larger than the driving torque of the lens group 1, the manual ring 30 rotates integrally with the ball race outer ring 26 and is provided at the tip of the manual ring 30. The lens group 1 is driven in the optical axis direction via the connecting pin 22. Further, when the lens group 1 is manually operated, that is, when the manual ring 30 is manually rotated, the friction torque between the manual ring 30 and the ball race outer ring 26 is set smaller than the holding force of the motor 5. Therefore, the ball race outer ring 26 does not rotate, that is, the driving force is not transmitted to the driving means 5 side, and only the manual ring 30 rotates using the contact surface 33a of the resin ring 33 and the steel plate 29 as the sliding surface. . Thus, in this embodiment, by using a differential mechanism that uses the magnetic force of the magnet 32, switching between electric and manual is realized without a changeover switch.
[0048]
In the photographic lens configured as described above, setting the position of the operating end of the lens group as in the first embodiment will be described. First, when the ball race outer ring 26 is driven by the ultrasonic motor 5, the manual ring 30 rotates integrally with the ball race outer ring 26 and moves the lens group 1. An annular encoder slit 25 is fixed to the inner periphery of the manual ring 30. Since the rotation range of the manual ring 30 is restricted by the stopper member 23, the lens group 1 stops at the operating end, and at the same time, the change in the output signal of the encoder 24 stops.
[0049]
If a state in which the output signal of the encoder 24 does not change is detected for a predetermined period of time despite the drive command being given to the ultrasonic motor 5, the end detection means in the CPU determines that the lens is operating, and is used for lens control. Clear the position counter to make it the control end. When the manual ring 30 reaches the stopper member 23, an impact is applied to the power transmission system. At the same time, the motor 5 continues to be driven for a predetermined time after the lens is stopped. However, the differential mechanism using a magnet acts as a torque limiter, and the resin ring Since the slip is generated by the load limiting means constituted by 33 and the steel plate 29, the impact is absorbed and the overload state is eliminated at the same time.
[0050]
As described above based on the two embodiments, with such a configuration, the position of the operating end of the lens group can be set only by the movement information detection means 24 that detects the lens movement amount. It can be controlled while recognizing the position.
[0051]
In this embodiment, the differential mechanism using the roller member as the load limiting means and the differential mechanism using the magnet as the load limiting means have been taken as an example. It may be anything other than.
[0052]
Next, a first initialization algorithm for positioning the lens at the servo origin in the present invention will be described. First, the servo configuration when driving the lens group in the optical apparatus of the present invention will be described with reference to FIG. Here, the lens group (optical means) to be driven is, for example, a focusing lens. A microcomputer (control means) 203 controls the focusing lens servo system. Reference numeral 207 denotes a timer for managing system timing.
[0053]
A motor (drive means) 205 for driving is connected to the focusing lens 206, and the motor 205 is driven through the drive unit 204 by the microcomputer 203. An encoder 201 that moves in synchronization with the focusing lens 206 is connected to the microcomputer 203 via a counter 202. Here, the encoder 201 and the counter 202 constitute one element as a movement amount detection means. The output from the encoder 201 is counted by the counter 202, and the counter value can be read by the microcomputer 203.
[0054]
  However, depending on the mechanism, even if the encoder 201 is connected to the motor 205 without being connected to the focusing lens 206, the structure may be such that the movement of the focusing lens 206 and the output of the encoder 201 can be synchronized. Further, the microcomputer 203 is connected with an EEPROM 208 for storing adjustment data of the optical device, a display LED 209 and a temperature sensor 210.
[0055]
Next, the relationship between the servo movement amount by the servo mechanism and the counter value of the counter 202 will be described with reference to FIG.
[0056]
  Hereinafter, the infinite distance indicating the object distance of the focusing lens 206 is referred to as INF, and the closest distance is referred to as MOD. Of the moving range in which the focusing lens 206 can physically move, the INF side is a mechanical end (end a) 301 and the MOD side is a mechanical end (end c) 302. The mechanical end 301 to the mechanical end 302 at this time is referred to as a first predetermined range. The movement amount is Cm308. Inside, there are an INF-side servo end (end b) 303 and a MOD-side servo end (electrical end) (end d) 304 that can be driven by the servo system. The servo end 303 to the servo end 304 at this time is referred to as a second predetermined range. The movement amount is assumed to be Cs307.
[0057]
Assuming that the servo end 303 on the INF side is the servo origin 305, an offset of the counter value exists between the mechanical end 301 on the INF side and the servo origin 305. When the offset value is Coff (306), the following equation is established.
[0058]
Cm ≧ Cs−Coff (a)
Here, when the counter value at the servo origin 303 is set to 0, and the focusing lens 206 is driven in the direction from the servo origin 303 to the servo end point 304 on the MOD side, the counter value of the counter 202 is counted up.
[0059]
For example, when the servo movement amount Cs is 10,000 pulses, the counter value of the counter 202 at the servo end point 304 on the MOD side is 10,000. Further, when the focusing lens 206 is driven from the servo origin 305 to the mechanical end 301 in the INF direction, the counter value of the counter 202 counts down, so that the offset pulse Coff takes a value of, for example, -20 pulses. Here, when the offset pulse Coff is a positive value, the equation (a) is as follows.
[0060]
Cm ≧ Cs + Coff (b)
The offset value (offset / pulse number Coff) 306 is determined by a design value, but may be slightly different depending on the assembly state of the system of the optical apparatus. Therefore, after assembling, the focusing lens 206 is moved to a position where an infinite distance comes out, and the amount of movement with the mechanical end 301 on the INF side is measured to absorb the assembling error. Further, this offset value 306 is stored in an EEPROM (storage means) 208, which is a rewritable storage medium after measurement, so that even when the infinite distance position is shifted after being put on the market, The offset value 306 can be readjusted.
[0061]
Here, an outline of initialization will be described. The origin of the focusing lens 206 is the position where the object distance is infinite. Therefore, in general, there are mechanical ends on the INF side and MOD side where the lens cannot physically move, and the lens moves by servo driving on the inside. In addition, the lens has an adverse effect such that the focal point moves slightly under temperature conditions, and even if there is a slip mechanism, a noise is generated when it hits the end of the mechanism.
[0062]
Therefore, when the machine end is designed to be overfocused at room temperature and the focusing lens 206 is moved by servo drive, the servo end is set inside the machine end. One of the servo ends on the INF side is defined as a servo origin 305. First, when power is turned on to the optical device, the drive unit starts to drive the focusing lens 206 to the INF side. The counter 202 that counts the pulse output from the encoder 201 is monitored and driven until the counter value of the counter 202 does not change within a predetermined time. That is, the driving is stopped in a state in which the focusing lens 206 collides with the mechanical end 301 where the servo origin exists and no pulse signal is output from the encoder 201 by the slip mechanism.
[0063]
Subsequently, a movement amount offset value Coff (305) from the mechanical end 301 to the position of the servo origin 305 is set in the counter 202, thereby completing the lens origin search.
[0064]
The above operation will be described with reference to the flowcharts of FIGS. When the power is turned on in the main routine 160 (step 101), the current counter value is read from the counter 202, the value is set to C0 (step 102), and the focusing lens 206 is driven in the INF direction (step 103). Then, FindLimit of subroutine 150 is called (step 116), and mechanical end 301 in the INF direction is detected.
[0065]
In order to observe the movement of the focusing lens 206 in the FindLimit of the subroutine 150, the counter value C1 is read from the counter 202 (step 104). The counter value C0 and the counter value C1 are compared (step 105). If they do not match, it is determined that the focusing lens 206 is moving. In step 106, C0 = C1 is replaced with the counter value, and the process returns to step 104. If it is determined in step 105 that the counter value C0 matches the counter value C1, it is determined that the focusing lens 206 is not moving, and the counter value C0 = C1 is set (step 107). The current time T0 is set to the timer 207. (Step 108).
[0066]
Subsequently, the current counter value C1 is read from the counter value 202 and compared with the counter value C0 stored in step 107 (step 110). If they do not match, it is determined that the focusing lens 206 is moving, and the routine returns to step 106. If it is determined that they match, it is determined that the focusing lens 206 is not moving, and the current time T1 is read from the timer 207 in step 111. Times T0 and T1 are compared by the following equation.
[0067]
T1-T0 ≧ Tk (1)
Here, Tk is a predetermined time, and indicates a time during which the counter value of the counter 202 determined that the focusing lens 206 is not moving does not change. For example, if Tk = 100 msec, it is determined that the focusing lens 206 is stopped if it is determined that the focusing lens 206 has not moved for 100 msec or longer.
[0068]
Therefore, if the expression (1) is not satisfied in step 112, it is determined that the focusing lens 206 does not satisfy the stop condition, and the process returns to step 109 to continue managing the counter value of the counter 202. If the expression (1) is established in step 112, it is determined that the focusing lens 206 satisfies the stop condition, and the drive is stopped in step 113. The current position stopped in step 114 is the mechanical end, and the process returns to the main routine 160.
[0069]
In step 115, the offset value Coff (306) of the movement amount from the mechanical end 301 on the INF side to the servo origin 305 according to the output of the temperature sensor 210 is read from the EEPROM 208, and the value is set to the counter value 202. In step 117, the focusing lens 206 is moved to the servo origin 303, and the origin of the focusing lens 206 is finished.
[0070]
Here, in step 117, the focusing lens 206 is returned to the servo origin 303, but may remain at the mechanical end 301 until a driving command for the focusing lens 206 is received.
[0071]
Next, a second initialization algorithm for positioning the lens of the present invention at both ends of the servo movement range will be described using the flowcharts of FIGS. When the power is turned on in the main routine 170 of FIG. 9 (step 120), the initialization NG counter INIT_NG_COUNTER is set to zero. The current counter value is read from the counter 202, and the value is set to C0 (step 122). Then, the focusing lens 206 is driven in the MOD direction (step 123), FindLimit in step 150 of the subroutine is called (step 124), and the mechanical end 302 in the MOD direction is detected.
[0072]
The detection of the mechanical end in the FindLimit of the subroutine 150 is as described above. After detecting the mechanical end 302 in the MOD direction, the current counter value C1 is set to Cmod (step 125). Next, in order to detect the mechanical end 301 in the INF direction, the focusing lens 206 is driven in the INF direction (step 126). As in the case of detecting the mechanical end 302 in the MOD direction, FindLimit of the subroutine 150 is called (step 127). After detecting the mechanical end 301 on the INF side, the current counter value C1 is set to Cinf (step 128).
[0073]
Since both mechanical ends 301 and 302 are detected, the distance calculation unit in the microcomputer 202 checks the value of (Cmod−Cinf), which is the amount of movement between the mechanical ends (first predetermined range), by the following equation ( Step 129). And by the distance comparison part in the microcomputer 202,
(Cmod-Cinf) ≧ (Cs-Coff) (2)
Judging. That is, the actual distance is compared with the reference distance.
[0074]
Here, Coff is assumed to take a negative value as described above. Further, it may be checked by a predetermined value Ck (Ck ≧ Cs) instead of the reference distance (Cs−Coff).
[0075]
If equation (2) is established in step 129 (distance comparison unit), the offset value Coff of the movement amount from the INF side mechanical end 301 to the servo origin 305 according to the output from the temperature sensor 210 in step 133 (step 306) ) Is read from the EEPROM 208, and the value is set in the counter 202. In step 134, the focusing lens 206 is moved to the servo origin 305, and the origin of the focusing lens 206 is finished.
[0076]
Here, although the focusing lens 207 is returned to the servo origin 303 in step 134, it may remain at the mechanical end 301 until a driving command for the focusing lens 206 is received. If the expression (2) is not satisfied in step 129, it is determined that the origin of the focusing lens 206 has not been successfully set, and the end detection limiter in the microcomputer 202 increments INIT_NG_COUNTER of the initialization NG counter by +1 (step 130). ). In step 131, in order to check INIT_NG_COUNTER of the initialization NG counter, it is compared with a predetermined value CNTng as shown in the following equation. Here, the end detection limiting unit (steps 130 and 131) limits the number of detections of the mechanical ends 301 and 302.
[0077]
INIT_NG_COUNTER ≧ CNTng (3)
When the expression (3) is not satisfied in step 131, the process returns to step 122, and the driving for initializing the focusing lens 206 is performed again. If the expression (3) is satisfied in step 131, it is determined in step 132 that the optical device system is defective (step 132). If the optical device system is determined to be defective, the optical device is displayed to the user. In order to notify the abnormal state of the system, in step 134, a malfunction is displayed by lighting or blinking the display LED (display unit) 209 and the initialization is completed.
[0078]
Further, if the servo drive is performed when it is determined that the system of the optical device is defective, the focusing lens 206 may run away, so that the focus adjustment by the focusing lens 206 can only be performed manually. I am trying to configure it.
[0079]
The example in which the origin of the focusing lens is set to INF has been described above. However, it is possible to set the origin on the MOD side, and it is also possible to apply the initialization algorithm to the zooming lens and the IRIS as well. Easy. Although the offset value Coff 306 is changed using the temperature sensor 210, a constant value may be used as long as the focus movement is not affected.
[0080]
【The invention's effect】
According to the present invention, as described above, an operation in which a predetermined lens group is an end portion of the first predetermined range among the lens groups constituting the photographing lens by appropriately setting a drive mechanism for driving and controlling the lens group. After driving to the end (mechanical end), the lens group is accurately and stably driven to the servo end (servo origin), which is the end of the second predetermined range for servo control inside the mechanical end. Thus, it is possible to achieve a lens barrel that can be driven and controlled and an optical device using the lens barrel.
[0081]
Further, according to the present invention, when a predetermined lens group among the lens groups constituting the photographic lens is driven to the operating end (end portion), the load limiting means appropriately set in the driving force transmission path is provided. A lens that can be driven accurately and stably while mitigating impact generated when the lens group is driven to the operating end of the mechanism by the load limiting means and preventing damage to the motor and power transmission unit. A lens barrel and an optical apparatus using the same can be achieved.
[0082]
Further, according to the present invention, when the predetermined lens group constituting the photographing lens is moved, a differential mechanism for manual and electric switching including a load limiting means is provided in the driving force transmission path, and the lens group is configured as a mechanism. By removing the impact generated when the actuator is driven to the upper operating end by the differential mechanism, the lens group is brought to the origin position without using a load limiting means separately and without using a conventional operating end detection switch. It is possible to achieve a lens barrel that can be driven and controlled with high accuracy and an optical apparatus using the lens barrel.
[0083]
According to the present invention, when the lens group is electrically driven, the absolute position of the lens group is recognized and controlled only by the movement information detecting device that detects the lens movement amount for detecting the relative movement amount of the lens group. be able to.
[0084]
Further, since the differential mechanism is provided in the manual / electric switching means for moving the lens, the impact generated when the lens group is driven to the operating end on the mechanism is removed by the differential mechanism. Therefore, it is possible to achieve a lens barrel and an optical device using the lens barrel that have an effect of eliminating the conventional switch for detecting the operating end without providing a load limiting unit.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an essential part of Embodiment 1 of the present invention.
FIG. 2 is a cross-sectional view of an essential part of Embodiment 2 of the present invention.
3 is an enlarged explanatory view of a part of FIG.
FIG. 4 is a cross-sectional view of a main part of a conventional lens barrel.
FIG. 5 is a principal block diagram for driving and controlling a lens group according to the present invention.
FIG. 6 is an explanatory diagram showing a relationship between counter values of the edge detecting means according to the present invention.
FIG. 7 is a flowchart of an initialization algorithm according to the present invention.
FIG. 8 is a flowchart of an initialization algorithm according to the present invention.
FIG. 9 is a flowchart of an initialization algorithm according to the present invention.
[Explanation of symbols]
1 Lens group
2 Lens holding frame
3 Fixed lens barrel
4 Manual ring
5 Ultrasonic motor
5a Stator
5b rotor
6 Stator rotation prevention member
7 Felt ring
8 Felt
9 Disc spring
10 Motor base
11 Belleville spring pressing member
12 Stator rotation prevention member fixed ring
13 Rotor output ring
14 Anti-vibration rubber
15 Roller member
16 ball race outer ring
17 Ball race inner ring
18 pin
19 ball race output ring
20 spheres
21 Lens drive ring
22 Connecting pin
23 Stopper member
24 Encoder
25 Encoder slit
26 ball race outer ring
27 Ball race inner ring
28 Ball race presser ring
29 Steel plate
30 Manual ring
31 York
32 Magnet
33 Resin ring
34 Moving lens group
35 Lens holder
36 Fixed lens barrel
37 Lens drive ring
38 1st gear
39 Second gear
40 motor
41 Connecting pin
42 Encoder
43 Encoder slit
44 resistors
45 brush
201 Encoder
202 counter
203 Microcomputer (CPU)
204 Drive unit
205 motor
206 Focusing Lens
207 timer
208 EEPROM
209 LED

Claims (8)

Driving means for driving the lens;
A power transmission system for transmitting the driving force of the driving means to the lens;
A stopper member disposed at a mechanical moving end of the lens;
A differential mechanism for alleviating an impact applied to the power transmission system by a sliding mechanism provided in the power transmission system when the movement of the lens is mechanically stopped by the stopper member;
Relative position detecting means for detecting the relative position of the lens;
When the power is turned on, the lens is driven toward the mechanical end, and it is detected that the lens is at the mechanical end based on the driving signal of the driving unit and the detection result of the relative position detecting unit. And a control means for driving the lens to an electrical end set inside the mechanical end. The lens barrel according to claim 1, wherein the control unit determines the electrical end of the lens based on movement information stored in advance in a storage unit. 3. The lens according to claim 2, wherein the lens barrel includes a temperature detection unit, and the control unit selects movement information stored in the storage unit based on a detection result of the temperature detection unit. A lens barrel. Driving means for driving the lens;
A power transmission system for transmitting the driving force of the driving means to the lens;
A stopper member disposed at a mechanical moving end of the lens;
A differential mechanism for alleviating an impact applied to the power transmission system by a sliding mechanism provided in the power transmission system when the movement of the lens is mechanically stopped by the stopper member;
Relative position detecting means for detecting the relative position of the lens;
When the power is turned on, the lens is driven toward the mechanical end, and it is detected that the lens is at the mechanical end based on the drive signal of the drive means and the detection result of the relative position detection means. And, after detecting the positions of both ends of the mechanical end, control means for driving and controlling the lens within the range of the electrical end set inside the mechanical end. Lens barrel. The lens barrel according to claim 4, wherein the control unit determines the electrical end of the lens based on movement information stored in advance in a storage unit. 6. The lens according to claim 5, wherein the lens barrel includes a temperature detection unit, and the control unit selects movement information stored in the storage unit based on a detection result of the temperature detection unit. A lens barrel. The said control means compares the space | interval of the both ends of the said mechanical end with the preset reference | standard space | interval, and detects the said mechanical end again based on a comparison result. Lens barrel.   An optical device for photographing, wherein the lens barrel according to any one of claims 1 to 7 is used.

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