JPH08338937A - Drive device and optical equipment using the same - Google Patents

Abstract

(57) [Abstract] [Purpose] To obtain a driving device and an optical device using the driving device, which can quickly and silently move a lens barrel holding a taking lens in the optical axis direction with a small driving force. A guide means for engaging a part of a driven body and movably guiding the driven body, an arm having a rotation axis in a direction substantially perpendicular to the guide direction of the guide means, and a linear motion of a rotary motion of the arm. Conversion means for converting into movement, and power means for transmitting the rotational force of the arm to the driven body via the conversion means to rotate the arm in order to move the driven body in the guide direction. When the driven body is moved by using each element, each element is set so that the central axis of the arm is substantially orthogonal to the guide direction at a substantially intermediate position in the movement range of the driven body.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving device and an optical apparatus using the driving device, and more particularly, to using a guide means for zooming or focusing a lens barrel which holds at least a part of a photographing lens as a driven body. It is suitable for a 35 mm film camera, a video camera, or the like, which is smoothly moved in the guide direction (optical axis direction).

[0002]

2. Description of the Related Art Conventionally, various driving devices have been proposed in which a lens barrel holding at least a part of a photographing lens is linearly moved in the optical axis direction for zooming and focusing.

For example, a lead screw is provided on the output shaft of a stepping motor, and a rack screw is locked on a driven lens such as a focus lens barrel or a variable power lens barrel, and the lead screw and the rack screw are engaged with each other. . As a result, the rotation of the stepping motor is converted into the movement of the focus lens barrel or the magnification varying lens barrel in the optical axis direction, and the focus lens barrel or the magnification varying lens barrel is counted by the stepping step number of the stepping motor. By doing so, the required amount of movement is made in the optical axis direction.

Further, the driving force of the motor is amplified by the speed reduction mechanism, and the torque is used to rotate the lens barrel having the cam to move the lens barrel. The movement amount of the lens barrel is controlled by providing a pulse encoder and counting the output pulses thereof.

Further, by using a so-called voice coil motor,
The lens barrel is moved and the lens barrel at that time is controlled by detecting the position of the lens barrel by a Hall element having a magnetoresistive effect.

In addition to this, a coil is provided in the magnetic field created by a permanent magnet magnetized to a plurality of poles, and the driven body is driven in a linear direction by energizing the coil, and the magnetic flux at the boundary portion of the magnetization is A position monitoring device is proposed in which the driven body is driven within a range in which the output from the hall element detected by the hall element and the movement of the driven body can be regarded as a substantially straight line.

[0007]

Generally, in a drive device for moving a lens barrel in the optical axis direction for focusing or zooming in an optical device such as a 35 mm film camera or a video camera, a high-speed drive is required as its drive condition. Is required, that large thrust can be obtained, that there is little vibration and noise, that control accuracy is high, etc.

Generally, in a driving device using a stepping motor as a driving power source, when an attempt is made to drive a lens barrel which is a driven body at a high speed, the stepping motor loses synchronization and the position of the lens barrel relative to an input pulse is set. Tends to be difficult.

Further, since the lens barrel is driven by step operation, vibration occurs. Therefore, in a video camera or the like, there is a problem that the vibration directly vibrates the microphone or becomes noise and is recorded by the video camera through the microphone.

Further, in a lens driving device in which a lens barrel, which is a driven body, is moved by using a so-called voice coil motor and the position of the lens barrel is detected by a magnetoresistive effect element, so-called direct driving is performed. The noise problem is solved. However, in addition to the weight of the lens barrel that is the driven body, the weight of the moving part of the voice coil motor is added to the moving weight, so the thrust required to move the lens barrel is stronger than the thrust required to move the lens barrel. Therefore, there is a problem in that the voice coil motor must be made large and a large amount of electric power is required.

According to the present invention, the guide means for linearly moving the driven body, the power means serving as a drive source, and the conversion means for converting the rotational driving force from the power means into the straight driving force are properly set. An object of the present invention is to provide a drive device that can drive a driven body quickly, smoothly and silently with a small drive force, and an optical device using the drive device.

[0012]

The drive device of the present invention comprises:
(1-1) Guide means for movably guiding a driven body by engaging a part thereof, an arm having a rotation axis in a direction substantially perpendicular to the guide direction of the guide means, and a rotary motion of the arm To a linear motion, and a power means for transmitting the rotational force of the arm to the driven body via the converting means to rotate the arm to move the driven body in the guide direction. When the driven body is moved by using and, each element is set so that the central axis of the arm is substantially orthogonal to the guide direction at a substantially intermediate position in the movement range of the driven body. Is characterized by.

(1-2) Guide means for movably guiding the driven body by engaging a part thereof, a rotor having permanent magnets magnetized to a plurality of poles, a field coil, and the field coil. Power means having a stator for energizing the rotor to generate torque in the rotor, conversion means for converting rotational motion of the rotor into linear motion and transmitting the linear motion to the driven body, rotation for detecting rotational position of the rotor When the driven body is moved by using position detecting means and control means for controlling the rotational position of the rotor based on an input signal from the outside and a signal from the rotational position detecting means, the field coil Each element is set so that the torque generated in the rotor when a predetermined amount of current is passed becomes maximum at a substantially intermediate position in the moving range of the driven body.

In particular, the rotation angle α of the rotor is defined as the angle between a pair of adjacent N poles and S poles of the permanent magnets of the rotor.
It is characterized in that the so-called electrical angle of 0 ° is set within the range of 24 ° <α <120 °.

The optical apparatus of the present invention comprises: (2-1) Guide means for movably guiding a lens barrel holding at least a part of a photographing lens by engaging with the part thereof, and a guide for the guide means. An arm having a rotation axis in a direction substantially perpendicular to the direction, a conversion means for converting the rotational motion of the arm into a linear motion, and the rotational force of the arm is transmitted to the lens barrel through the conversion means. When the lens barrel is moved by using the power means for rotating the arm to move the lens barrel in the guide direction, the center of the arm is located at a substantially intermediate position within the moving range of the lens barrel. It is characterized in that image information is formed on a predetermined surface by the photographing lens by using a driving device in which each element is set so that its axis is substantially orthogonal to the guide direction.

(2-2) Guide means for movably guiding a lens barrel for holding at least a part of the taking lens by engaging a part of the lens barrel, and a rotor having permanent magnets magnetized to a plurality of poles. A field coil and a power means having a stator for energizing the field coil to generate a torque in the rotor, a conversion means for converting a rotational movement of the rotor into a linear movement and transmitting the linear movement to the lens barrel, The lens barrel is constructed by using a rotational position detecting means for detecting the rotational position of the rotor, and a control means for controlling the rotational position of the rotor based on an input signal from the outside and a signal from the rotational position detecting means. When moving, a drive device in which each element is set so that the torque generated in the rotor when a predetermined amount of current is applied to the field coil is maximized at a substantially intermediate position in the moving range of the lens barrel. It is characterized in that so as to form an image information onto a predetermined surface by the photographing lens used.

In particular, the rotation angle α of the rotor is set within the range of electrical angle of 24 ° <α <120 °.

[0018]

Embodiment 1 FIG. 1 is a schematic view of the essential portions of Embodiment 1 when the driving device of the present invention is applied to an optical device. FIG. 2 is an explanatory diagram showing the relationship with the output signal from the Hall element at each position of the rotor in FIG.

In the figure, reference numeral 1 denotes a permanent magnet, which is formed by, for example, molding a neodymium plastic permanent magnet into a smooth shape, and its outer diameter portion is magnetized to have two poles, and its magnetizing waveform is a sine wave. It is wavy. The two-pole sinusoidal magnetizing waveform is obtained by magnetizing in a parallel magnetic field with the inner diameter smaller than the outer diameter of the permanent magnet 1. Reference numeral 2 denotes a first stator, which is formed by punching and stacking a silicon steel plate, for example, and has a magnetic pole portion 2a facing the permanent magnet 1 and an extension portion 2b. 3 is the second stator,
For example, it is made by punching and laminating a silicon steel plate by press working, and has a magnetic pole portion 3 a facing the permanent magnet 1.

Reference numeral 4 is a coil (field coil), which is made by winding a copper wire around a hollow bobbin (not shown).
Is extended to the extension portion 2b of the stator 2. Reference numeral 5 denotes an arm, which is formed by molding polycarbonate resin, for example, and has a rotary shaft 6 and a sliding shaft 7 which are integrally provided, and the permanent magnet 1 is fixed on the rotary shaft 6 side. 19 is formed. 5a is a central axis of the arm 5.

A rotary shaft 6 formed integrally with the arm 5 is rotatably supported by a bearing of a case (not shown). Reference numeral 18 denotes a motor, which has a rotor 19, a first stator 2, a second stator 3, a coil 4, and an arm 5.

Reference numeral 8 is a lens barrel as a driven body,
For example, it is made by molding polycarbonate resin, and the first sliding groove 8a, the sliding hole 8b, and the second sliding groove 8 are formed in a part thereof.
c, a spring locking portion 8d is provided, and a lens 11 (also referred to as a "photographing lens") 11 which is a part of the photographing lens, which is a moving body, is held on the inner peripheral portion thereof.

In the first sliding groove 8a of the lens barrel 8, the sliding shaft 7 made integrally with the arm 5 is fitted. A trailing spring 17, which is made by pressing phosphor bronze, for example, is fixed to the spring locking portion 8d of the lens barrel 8. The trailing spring 17 urges the sliding shaft 7 to the side surface of the sliding groove 8 a of the lens barrel 8. The sliding shaft 7 and the sliding groove 8a constitute one element of conversion means for converting the rotational movement of the arm 5 into a linear movement and transmitting it to the lens barrel 8.

Reference numerals 9 and 10 respectively denote the first and the first guide means.
It is a second guide bar and is arranged parallel to the optical axis of the taking lens 11. The first guide bar 9 is made of, for example, stainless steel, and both ends thereof have a fixed lens barrel 16
It is fixed by well-known means such as press fitting. Furthermore the first
The guide bar 9 of is fitted into the sliding hole 8b of the lens barrel 8,
The lens barrel 8 is movably supported in the lengthwise direction of the first guide bar 9.

The second guide bar 10 is made of, for example, stainless steel, and both ends thereof are fixed to the fixed lens barrel 16 by known means such as press fitting. Further, the second guide bar 10 is fitted in the sliding groove 8c of the lens barrel 8,
The lens barrel 8 is movably supported in the length direction of the second guide bar.

Reference numeral 12 is a Hall element as a rotational position detecting means for detecting the rotational position of the arm 6. The hall element 12 is composed of a well-known hall element, and is fixed to a case (not shown) so as to face the outer peripheral portion of the permanent magnet 1 with a slight gap. The hall element 12 outputs an output signal proportional to the magnetic flux density on the surface of the permanent magnet 1 as the permanent magnet 1 rotates.

Reference numeral 13 is an amplifier circuit, and its input terminal 13
a is electrically connected to the output terminal of the hall element 12, and amplifies the output signal of the hall element 12. Also amplifier circuit 1
3 also includes a circuit for supplying bias power to the Hall element 12.

A control circuit 14 has a first input terminal 1
4a, a second input terminal 14b, and an output terminal 14c. The first input terminal 14a of the control circuit 14 is
For example, it is electrically connected to a focus control circuit of a video camera.

Further, the target position of the photographing lens 11 which is a moving body is inputted to the first input terminal 14a of the control circuit 14 as a voltage value as a control command signal. The second input terminal 14b of the control circuit 14 is the output terminal 13b of the amplifier circuit 13.
Is electrically connected to Further, the current position of the taking lens 11, which is a moving body, is input as a voltage value to the second input terminal 14b of the control circuit 14. The control circuit 14 controls the voltage corresponding to the target position of the photographing lens 11 input to the first input terminal 14a and the voltage corresponding to the current position of the photographing lens 11 input to the second input terminal 14b. The difference is amplified and a voltage corresponding to the difference between the target position and the current position is output to the output terminal 14c.

Reference numeral 15 denotes a drive circuit, which has an input terminal 15
a and the first and second output terminals 15b and 15c. The input terminal 15a is electrically connected to the output terminal 14c of the control circuit 14. Also, the first and second output terminals 15
b and 15c are electrically connected to the coil 4, respectively.

In the drive circuit 15, when the voltage value applied to the input terminal 15a is higher than a predetermined voltage, the voltage output to the first output terminal 15b is the second output terminal 15c.
A voltage proportional to the absolute value of the difference between the predetermined voltage and the voltage value input to the input terminal 15a so as to be higher than the voltage output to the first and second output terminals 15b and 15c.
Is applied to the coil 4 via.

Further, the drive circuit 15 has the first voltage when the voltage value applied to the input terminal 15a is lower than a predetermined voltage.
Voltage output to the output terminal 15b of the second output terminal 1
A voltage proportional to the absolute value of the difference between the predetermined voltage and the voltage value input to the input terminal 15a is set to be lower than the voltage output to 5c, and the first and second output terminals 15b, 1
It is applied to the coil 4 via 5c.

R is the length of the arm 5, and the rotor 19
The distance from the rotation center 6 to the center of the sliding shaft 7 is shown. L represents the stroke amount of the taking lens 11 which is a driven body in the optical axis direction. θ indicates a rotation angle about the rotation axis 6 of the arm 5.

Next, the operation of this embodiment will be described. When a command signal corresponding to the target position of the lens barrel 8 that is the driven body is input as a voltage to the first input terminal 14a of the control circuit 14, the control circuit 14 causes the difference between the output signal of the hall element 12 and the command signal. Is input to the drive circuit 15 so as to amplify the difference and reduce the difference to zero. Drive circuit 15
Applies the voltage at this time to the coil 4 of the motor 18. Accordingly, the rotor 19 of the motor 18 rotates to a position where the output voltage of the hall element 12 outputs a value corresponding to the command signal.

At this time, the rotor 19 is rotated by the arm 5
Is transmitted to the lens barrel 8 through the lens barrel 8, and the lens barrel 8 moves to a position corresponding to the command signal. As described above, in this embodiment, the arm 5 is directly fixed to the rotor that is the driving power source to drive the lens barrel 8.

By the way, the relationship between the torque generated by the motor 18 for driving the lens barrel 8 and the thrust acting on the lens barrel 8 is the thrust F for driving the lens barrel 8 and the generation of the motor 18. Letting T be the torque to be applied, the relationship F = (T / R) × cos θ (1) is established. As is clear from the equation (1), the larger the rotation angle θ of the arm 5, the larger the torque that should be generated by the motor 18 for driving the lens barrel 8. In the first embodiment shown in FIG. 1, in order to minimize the torque that should be generated by the motor 18 necessary for driving the lens barrel 8, the total stroke L of the lens barrel 8 is 1
1 which constitutes the motor 18 in the position of / 2
The boundary between the magnetic poles of the permanent magnet 1 of 9 is opposed to the centers of the magnetic pole portions 2a and 3a of the first and second stators 2 and 3, and the arm 5 is perpendicular to the guide bars 9 and 10 at that position. ing.

Further, in this embodiment, the torque T generated by the motor 18 is expressed as T = T ₀ cos θ (2) with respect to θ shown in FIG. Here, T ₀ is the peak value of the torque generated by the motor 18. Further, if the length R of the stroke L and the arm 5 of the lens barrel 8 the rotation angle of the arm 5 at the stroke end of the lens barrel 8 and _{θ 1 L / 2 = Rsinθ 1} ‥‥‥ that (3) The relationship between the peak value T _{0 of the} torque to be generated by the motor 18, the stroke amount L of the lens barrel 8 and the arm length R is expressed by the equations (1), (2) and (3). When the thrust required to drive 8 is F ₀ , it can be expressed as T ₀ = F ₀ × R ³ / (R ² − (L / 2) ² ) ... (4). In the present embodiment, the relationship between the stroke L and the length R at which the formula (4) is minimized so that the output torque of the motor 18 is minimized in order to downsize the motor 18 and downsize the drive device, I.e.

[0038]

[Equation 1] The rotation angle of the arm 5 with respect to the entire stroke of the lens barrel 8 at this time is 70.6 °.

By the way, when the present invention is applied, space may be prioritized over power consumption depending on the driving device to which the present invention is applied. In this case, it may be necessary to shorten the length of the arm 5, but in that case also, it is preferable that the rotation angle of the arm 5 is within an electrical angle of 120 ° in order to drive the lens barrel 8 efficiently. . On the contrary, it may be necessary to use a control circuit having a simple structure. In this case, it is necessary to increase the arm length and reduce the rotation angle of the rotor so that the torque generated by the motor changes less when a predetermined current is applied during the entire stroke of the lens barrel. Is coming.

In such a case, the rotation angle of the arm 5 is set to 2
It is preferable to select in the range of 4 ° to 60 °, so that the torque that must be generated in the motor can be less than twice the minimum value.

As a result, in this embodiment, the rotation angle of the rotor 19 is set within the range of 24 ° to 120 ° in terms of electrical angle.

Next, the position control of the drive unit according to the first embodiment of the present invention will be described. In this type of device, it is difficult to control the position of the lens barrel 8 with high accuracy unless the movement of the lens barrel 8 as a driven body is linear with respect to the command signal.

In the first embodiment of the present invention, the permanent magnet 1 is magnetized in a sinusoidal shape, and the mounting angle of the arm 5 and the hall element 12 is devised to adjust the position of the lens barrel 8 and the output voltage of the hall element 12. The linearity of the lens facilitates the control of the lens barrel 8.

Next, the position of the lens barrel 8 and the Hall element 12
1 and 2 about the mounting angles of the permanent magnet 1, the arm 5 and the hall element 12 for giving linearity to the output voltage of
Will be explained.

In the embodiment of the drive device shown in FIG. 1, the mounting direction of the arm 5 (direction of the central axis 5a) coincides with the direction of the boundary of the magnetic poles of the permanent magnet 1. Hall element 1
2 is arranged at a position facing the boundary of the magnetic poles of the permanent magnet 1 when the arm 5 is at an angle forming a position perpendicular to the longitudinal direction of the first and second guide bars 9, 10.

Next, the output signal of the Hall element 12, the rotation angle of the rotor 19 and the position of the lens barrel 8 will be described with reference to FIG. In FIG. 2, the horizontal axis θ indicates the rotation angle of the rotor 19. Particularly, the position where the arm 5 is perpendicular to the longitudinal direction of the first and second guide bars 9 and 10 is represented as 0. The vertical axis eout is the Hall element 1
2 represents the output signal from 2. Furthermore, x is the lens barrel 8
The position where the arm 5 is in the direction perpendicular to the longitudinal direction of the first and second guide bars 9 and 10 is represented as 0.

Since the permanent magnet 1 is magnetized in a sinusoidal shape, the output voltage eout from the Hall element 12 with respect to the rotation angle θ of the rotor 19 is sinusoidal as shown in FIG. 2 (A). become. Also, the rotation angle θ of the rotor 19
The position x of the lens barrel 8 with respect to is equal to the component of the rotation axis 5 of the sliding shaft 7 in the longitudinal direction of the first and second guide bars 9 and 10 due to the configuration described with reference to FIG. In addition, as shown in FIG.

Since the output voltage eout of the Hall element 12 and the position x of the lens barrel 8 are sinusoidal with respect to the rotation angle θ of the rotor 19, the output from the Hall element 12 with respect to the position x of the lens barrel 8 is changed. The voltage eout is shown in Fig. 2.
It becomes a straight line as shown in (C). As a result, the position of the lens barrel 8 is easily controlled based on the output voltage eout from the Hall element 12.

Next, the drive circuit according to the first embodiment of the present invention will be described with reference to FIG. In FIG. 3, the same components as those described in FIG. 1 are designated by the same reference numerals. In FIG. 3, 12 is the Hall element described with reference to FIG. 1, 13 is an amplifier circuit, 14 is a control circuit, 15 is a drive circuit, and 4 is a coil. Further, 21 to 48 are resistors, 49 to 54 are operational amplifiers, and 55 is a capacitor.

The resistor 21 is connected to the first input terminal of the Hall element 12 and the power supply, and determines the bias current of the Hall element 12. Since the bias current of the Hall element 12 is a factor that determines the gain of the Hall element 12, the Hall element 12
The gain of is determined by the resistor 21. Resistors 22, 2
3, 24, 25, 26, 27 and the operational amplifier 49 constitute a well-known differential amplifier. The first and second input terminals of the differential amplifier are connected to the first and second output terminals of the Hall element 12.

The resistors 32 and 33 are for creating a reference voltage, and these resistors 28, 29, 30, 31 and the operational amplifier 50 constitute a well-known differential amplifier. The first input terminal 14a of the differential amplifier including the operational amplifier 50 is an input terminal of the driving device according to the present embodiment, and is connected to an external command signal generating device such as an automatic focus detecting device in a video camera. There is.

The second of the differential amplifier including the operational amplifier 50
Is connected to the output terminal of the differential amplifier including the operational amplifier 49, and the differential amplifier including the operational amplifier 50 outputs the command signal given from the outside and the output from the hall element 12 corresponding to the rotational position of the rotor 19. Amplify the difference between the amplified signals. Resistors 34, 35, 36, 3
7, 38, 39, 40, 41, the condenser 55, and the operational amplifiers 52, 53 constitute a speed signal amplifier circuit.
The input terminal of this speed signal amplifier circuit is the Hall element 12
The speed signal amplifier circuit is connected to the output terminal of a differential amplifier including an operational amplifier 49 for amplifying the output signal from the Hall element 12. The speed signal amplifier circuit amplifies a change in the output signal from the Hall element 12, which represents the rotation speed of the rotor 19.

The resistors 42, 43, 44, 45 and the operational amplifier 51 constitute a well-known amplifier, the input terminal 15a of which is the first output terminal 14c of the control circuit 14 and the operational amplifier 5.
The output terminal of the differential amplifier circuit including 0 and the second of the control circuit 14
Is connected to the output terminal of the speed signal amplifier circuit, which is the output terminal of the.

The amplifier circuit including the operational amplifier 51 outputs a voltage corresponding to the reference voltage corresponding to the command signal and the position shift of the lens barrel 8 and also to the rotation speed of the rotor 19. The resistors 46, 47, 48 and the operational amplifier 54 constitute a well-known inverting amplifier, the first input terminal of which is connected to the output terminal of the amplifier including the operational amplifier 51, and the output voltage of the amplifier including the operational amplifier 51 with respect to the reference voltage. Outputs the inverted voltage.

The output terminal of the amplifier circuit including the operational amplifier 51 is the first output terminal 15b of the drive circuit and is connected to the first terminal of the coil 4. The output terminal of the amplifier circuit including the operational amplifier 54 is the second output terminal 1 of the drive circuit.
5c, which is connected to the second terminal of the coil 4.

With such a circuit configuration, the driving apparatus of this embodiment can accurately drive the lens barrel 8 which is the driven body in response to the command signal. By the way, when the taking lens is driven by the driving device according to the present invention as in the first embodiment of the present invention described so far, the gain of the driving circuit is set so that the defocus amount of the taking lens in the optical axis direction is the allowable confusion circle diameter. It is desirable to set so that a current sufficient to drive a load due to the weight of the taking lens 8 or the like flows through the coil 4 of the motor 18 when the lens is moved by a value that is less than half of the above. By doing so, an image with no out-of-focus can be obtained.

FIG. 4 is a schematic view of a part when the driving device of the present invention is applied to an optical device. In FIG. 4, the parts described with reference to FIG. 1 are given the same reference numerals.

In FIG. 4, reference numeral 55 denotes a first fixed lens barrel, to which the first fixed lens group is fixed. 56 is the first
Is a movable lens group, and a variable power lens is fixed.
Reference numeral 57 denotes a second fixed lens barrel, to which the second fixed lens group is fixed. Reference numerals 58 and 59 denote first and second guide bars for the variable power lens, which are fixed to the first and second fixed lens barrels, and slide holes and slides provided in the first moving lens barrel 56. The first moving lens barrel 56 is fitted in the groove and movably supported in the optical axis direction.

Reference numeral 61 is a first motor, and a screw shaft 61a is provided on the output shaft. Reference numeral 60 denotes a rack member, which is mounting holes 56a, 56 provided in the first movable lens barrel 56.
The rack screw portion is engaged with the screw shaft 61a of the motor while being attached to the motor b. A reset sensor 62 resets the position of the first movable lens barrel. With such a configuration, the variable power lens moves in the optical axis direction as the motor 61 rotates. 63 and 64 are diaphragm springs,
A pressing plate 65 regulates the position of the diaphragm spring.

Reference numeral 66 denotes a diaphragm driving motor, and the diaphragm blades 63 and 64 open and close according to the rotation thereof. Reference numeral 16 is a third fixed lens barrel, and 8 is a second movable lens barrel on which a focus competition lens is fixed. Reference numerals 9 and 10 denote guide bars of lenses for the first and second focus competitions, which are fixed to the second fixed lens barrel 57 and the third fixed lens barrel 16 and of the second movable lens barrel 8. The second moving lens barrel 8 is movably supported by being fitted in the sliding hole 8b and the second sliding groove 8c. Reference numeral 18 denotes a second motor, which is fixed to the third fixed lens barrel 16 and has its output shaft fitted with the first sliding groove 8a of the second moving lens barrel 8 to provide the second motor. 2nd by rotation of 18
The moving lens barrel 8 is driven in the optical axis direction.

By using the driving device having such a structure, the lens barrel can be driven quietly, at high speed, and accurately.

5 (A) and 5 (B) are a front view and a side view of the essential parts of the second embodiment of the present invention. In this embodiment, the first embodiment
The power source for driving the arm 5 is different from that in FIG.
In FIG. 5, 67, 68, 69, and 70 are gears, respectively, which are made by molding a material having excellent slidability such as polyacetal resin. Reference numeral 71 is a known DC motor. Further, 72 is a rotating shaft, and 73 and 74 are base plates. The rotor 19 is composed of a cylindrical permanent magnet 1, an arm 5, a rotating shaft 6, a fitting shaft 7, a gear 67 and the like.

The arm 5, the rotary shaft 6 and the fitting shaft 7 are integrally formed, and the arm 5 is oriented at a right angle to the first guide bar 9 at the center position of the entire stroke of the lens barrel 8. Has become. The permanent magnet 1 and the gear 67 are fixed to the rotary shaft 6 by known means such as press fitting. The Hall element 12 is provided at a position where the arm 5 faces a direction perpendicular to the first guide bar 9 and at a position facing the boundary of the magnetic poles of the permanent magnet 1. The gear 68 and the gear 69 are integrally molded and fixed to the rotating shaft 72 by means such as press fitting.

The gear 70 is fixed to the output shaft of the motor 71 by known means such as press fitting. The base plates 73 and 74 rotatably support the rotary shafts 6 and 72, respectively.
Further, the hall element 1 is fixed to the main plate 73 by a fixing means (not shown).
2 is fixed. Further, the DC motor 7 is attached to the main plate 74.
1 is fixed. Gear 6 fixed to rotor 19
The numeral 7 meshes with the gear 69, and the gear 68 rotating integrally with the gear 69 meshes with the gear 70 fixed to the motor shaft.

With such a configuration, the rotation of the motor 71 is transmitted to the rotor 19 via the gears 70, 68, 69, 67, and the rotor 19 rotates so that the lens barrel 8 as a driven body is moved in the optical axis direction. Are driven to. Further, the Hall element 12 is positioned in the position of the lens barrel 8 by a method of performing sinusoidal magnetization on the permanent magnet described in the first embodiment of the present invention or a method of devising the cam shape of the sliding groove provided in the lens barrel. The voltage value corresponding to is output. With such a configuration, the drive circuit described in FIG. 3 can be used as it is.

In the second embodiment of the present invention described above, a DC motor is used as a driving power source, and its torque can be amplified by a gear to be used for driving the lens barrel. It is possible to drive with
In particular, it is suitable when the weight of the driven body is heavy.

[0067]

As described above, according to the present invention, the guide means for linearly moving the driven body, the power means as the drive source, and the conversion for converting the rotational driving force from the power means into the straight driving force. By appropriately setting the means and the like, it is possible to achieve a drive device that can quickly, smoothly and quietly drive a driven body with a small drive force, and an optical device using the same.

[Brief description of drawings]

FIG. 1 is a schematic view of a main part of a first embodiment of the present invention.

FIG. 2 is an explanatory view showing an output signal from a Hall element at each position of the rotor shown in FIG.

FIG. 3 is a circuit explanatory diagram of each element in FIG.

FIG. 4 is a perspective view of an essential part of a first embodiment of the present invention.

FIG. 5 is a schematic view of the essential portions of Embodiment 2 of the present invention.

[Explanation of symbols]

 1 Permanent Magnet 2, 3 Stator 4 Coil 5 Arm 8 Lens Barrel (Driven Body) 12 Hall Element 13 Amplifying Circuit 14 Control Circuit 15 Drive Circuit 16 Guide Means 18 Motor 19 Rotor

Front page continued (72) Inventor Hidekage Sato 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (6)

[Claims] 1. A guide means for movably guiding a driven body by engaging a part thereof, an arm having a rotation axis in a direction substantially perpendicular to a guide direction of the guide means, and a rotary motion of the arm. To a linear motion, and a power means for transmitting the rotational force of the arm to the driven body via the converting means to rotate the arm to move the driven body in the guide direction. When the driven body is moved by using and, each element is set so that the central axis of the arm is substantially orthogonal to the guide direction at a substantially intermediate position in the movement range of the driven body. A drive device characterized by. 2. A guide means for movably guiding a driven body by engaging a part of the driven body, a rotor having permanent magnets magnetized to a plurality of poles, a field coil, and energizing the field coil. Power means having a stator for generating torque in the rotor, conversion means for converting rotational motion of the rotor into linear motion and transmitting the linear motion to the driven body, rotational position detection means for detecting rotational position of the rotor Then, when the driven body is moved by using an input signal from the outside and a control means for controlling the rotational position of the rotor based on the signal from the rotational position detecting means, a predetermined amount is applied to the field coil. A drive device in which each element is set such that the torque generated in the rotor when an electric current is passed becomes maximum at a substantially intermediate position in the movement range of the driven body. 3. The drive device according to claim 2, wherein the rotation angle α of the rotor is set within an electrical angle range of 24 ° <α <120 °. 4. A guide means for movably guiding a lens barrel for holding at least a part of a photographing lens by engaging the lens barrel with a part thereof, and a rotary shaft in a direction substantially perpendicular to a guide direction of the guide means. An arm having the same, a conversion means for converting a rotational movement of the arm into a linear movement, and a rotational force of the arm transmitted to the lens barrel through the converting means to move the lens barrel in the guide direction. When the lens barrel is moved by using power means, the drive is set such that the central axis of the arm is substantially orthogonal to the guide direction at a substantially intermediate position within the moving range of the lens barrel. An optical apparatus characterized in that image information is formed on a predetermined surface by the taking lens using an apparatus. 5. A guide means for movably guiding a lens barrel for holding at least a part of a photographing lens by engaging with a part thereof, a rotor having permanent magnets magnetized to a plurality of poles, and a field coil. And a power means having a stator for energizing the field coil to generate torque in the rotor, a converting means for converting a rotational motion of the rotor into a linear motion and transmitting the linear motion to the lens barrel, and a rotor of the rotor. When moving the lens barrel by using a rotational position detecting means for detecting a rotational position, and a control means for controlling the rotational position of the rotor based on an input signal from the outside and a signal from the rotational position detecting means. , Each element is set such that the torque generated in the rotor when a predetermined amount of current is applied to the field coil is maximized at a substantially intermediate position in the moving range of the driven body. Tosu An optical device characterized in that image information is formed on a predetermined surface by the taking lens using a driving device. 6. The optical device according to claim 5, wherein the rotation angle α of the rotor is set within an electrical angle range of 24 ° <α <120 °.