JPS6389824A - Power focusing device - Google Patents

Abstract

PURPOSE:To attain accurate focusing by immediately stopping a lens driving source at the time of stopping the operation of a focus ring during the driving of a lens. CONSTITUTION:A pulse is generated from a pulse generating means 6 in accordance with the rotation of the focus ring 1. When the rotation of the ring 1 is stopped during the driving of the lens driving source 4 and the lens 3 in accordance with the pulse signal, the succeeding pulse is not generated even after the passage of a prescribed time. Thereby, a timer circuit in an immediate stop means 15 is timed up and a signal for turning a set value to zero is outputted from the means 15 to an extent of driving setting means 10. Since the driving source 4 is immediately stopped, the driving source 4 is not rotated for a comparatively long period after stopping the rotation of the ring 1. Thereby, the driving source 4 immediately follows the operation of the ring 1 and accurate focusing can be attained.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] This invention converts a manual focusing operation in a camera or its interchangeable lens into an electrical signal, etc., and uses the electrical signal, etc. to drive and control a power source such as a motor. The present invention relates to a power focusing device configured to drive a focusing lens to faithfully follow the focusing operation.

[Background of the invention]

Many modern cameras and their interchangeable lenses are equipped with autofocus devices (hereinafter abbreviated as AF), and such cameras and interchangeable lenses require human eyes and hands to perform focusing operations. The demand for cameras with AF is increasing because they are very easy to use and do not require AF.

However, AF-equipped cameras and AF-equipped interchangeable lenses have the disadvantage that you cannot intentionally take out-of-focus photos even if you want to, and the shutter does not operate until the subject is in focus, so the shutter does not operate for a moment. This has the disadvantage that it is easy to miss a photo opportunity, so people who want to take a variety of photos using various shooting techniques and the need to capture a momentary photo opportunity even if the focus is a little blurry. For those who own cameras, AF-equipped cameras and AF-equipped interchangeable lenses have become rather difficult-to-use photographic equipment. Therefore, when taking photos that do not require a specific subject to be strictly in focus or photos that are intentionally out of focus, it is conventional to use the traditional method of manually adjusting the focus. Interchangeable lenses and cameras have been used, but in various shooting situations, it has become necessary to use AF to take a focused photo, or a manual focus mechanism (hereinafter abbreviated as MF). ), it was desirable to be able to perform both autofocus and manual focus operations with a single interchangeable lens.

Against this background, photoconvertible lenses that can perform both autofocus and manual focus operations have been manufactured. This known interchangeable lens is configured so that during autofocus, the lens is driven by a motor, and during manual focus, the lens is driven manually by switching a clutch. Therefore, it is possible to correspond to various shooting situations.

However, since this known interchangeable lens uses a dog clutch to switch between AF and MP, there is a risk that the lens may move due to the mechanical shock that occurs when switching the clutch and the meshing tolerance of the clutch. Another drawback was that the clutch switching operation was complicated. Further, in manual focus operation, since the lens is driven by hand, the lens drive speed is slower than in autofocus operation, and moreover, it requires a considerable amount of operating force, making it difficult to use.

Therefore, in order to solve the above-mentioned problems of the known interchangeable lenses, the lens is driven by a motor even during manual focus operation. It has been proposed to mount a so-called power focus device on an interchangeable lens together with an AP, and several proposals have also been made regarding the power focus device.

Among the proposals regarding the power focus device, there is a proposal to use a tongue switch instead of the conventionally known focus ring (focus ring), and a proposal to use a rotation angle of a ring-shaped rotary switch that interlocks with the focus ring during manual focus operation. There is a proposal to change the lens drive speed in .

However, the former proposal has the drawback that the operation method is very different between the button switch and the conventionally known focus ring, making it difficult to use.Also, in the latter proposal, the lens does not move even if the hand is stopped. does not stop,
At this time, in order to stop the lens movement, it is necessary to return the rotary switch to the neutral position, which has disadvantages in that operability is poor and precise focusing is impossible. Therefore, it has been difficult to put the power focus devices according to both of the above proposals into practical use. Therefore, no! In order to make the Wharf Orcus device practical, the hand-operated operating member must be configured so that it can be operated in exactly the same way as a conventional focus ring, and the movement of the device that drives the lens must be the same as the movement of the hand. It is necessary to be structured in such a way that it can respond quickly and faithfully.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a f-wharf focus device that is practical, easy to operate, and capable of precise focusing, without the drawbacks inherent in the conventional proposals as described above.

[Summary of the invention]

A power focus device according to the present invention includes a focus ring that is rotatably operated by hand, a pulse generating means that generates a pulse signal in conjunction with the focus ring, and a
Focus ring rotation direction detection means detects the rotation direction of the focus ring from the Susu signal, focus ring rotation amount detection means detects the rotation amount of the focus ring from the Norse signal, and detection in the focus ring rotation direction detection means Drive direction setting means for setting the drive direction of the lens drive source based on the result, and drive amount setting means for setting the drive amount of the lens drive source based on the detection result detected by the focus ring rotation amount detection means. When the operation of the focus ring is stopped while the lens driving source is being driven, a timer circuit detects the time during which the pulse signal is not generated, and the timer circuit determines that the pulse signal will not be generated for a set time period or longer. The present invention is characterized by comprising an immediate stop means for immediately stopping the lens drive source when detected.

The Wharf Orcus device of the present invention has the advantage that it is extremely easy to use because it uses the focus ring used in conventional MF as a manual focus operation member, and also has the advantage that it is extremely easy to use because it is equipped with the instant stop means. When the operation of the lens is stopped, the lens drive is also stopped immediately.As a result, according to the present invention, an easy-to-use power focusing device is provided.

[Embodiments of the invention]

The present invention will be described in detail below with reference to the drawings.

FIG. 1 is a diagram showing a schematic configuration of a focusing device in a camera or an interchangeable lens equipped with a power focusing device 100 and AF.

In FIG. 1, reference numeral 100 denotes a power focus device of the present invention, and the device 100 includes a focus ring 1 that can be rotated with a finger, and operations necessary for a focus operation in accordance with the rotation operation of the focus ring 1. A manual focus calculation circuit 2 that calculates the amount, etc., a drive source 4 such as a motor for driving the focusing lens 3 in the direction of arrow f (optical axis direction), and a drive control circuit 5 that controls the drive source 4. and are included. The drive control circuit 5 also serves as a drive control circuit for AF, and an AF calculation circuit 98 is connected to the circuit 5, and an output signal of a known AF sensor 99 is input to the AF calculation circuit 98. .

FIG. 2 is a diagram showing the functions of the main parts in an embodiment of the power focusing device of the present invention as a block diagram of the control system, and FIG. 3 is a diagram showing the actual power focusing device shown in FIG. 2. This shows the electrical configuration.

In FIG. 2, 1 is a focus ring that is rotated by a person's fingers, and 6 is a z!
a first pulse generating means for generating a JV signal; 3 a focusing lens provided in a barrel of a camera; 4 a drive source such as a motor for driving the lens 3; 7 a first pulse generator; /Focus ring rotational direction detection means for detecting the rotational direction of the focus ring 1 by the pulse signal generated from the IP pulse generation means 6; 8 detects the rotation amount (rotation angle) of the focus ring 1 from the f pulse signal; The focus ring rotation amount detection means 9 detects the rotation direction detected by the focus ring rotation direction detection means 7 in the drive direction of the drive source 4 (
drive direction setting means 10 for setting the drive amount (rotation angle) corresponding to the rotation amount detected by the focus ring rotation amount detection means 8 as the drive amount of the drive source 4; 11 is a second pulse generating means that generates a pulse signal proportional to the movement of the driving source 4 or the lens 3; 12 is a pulse generation speed detecting means that detects the generation speed of the pulse signal generated from the first notarus generating means 6; , 13 is a drive speed setting means for setting the drive speed of the drive source 4 according to the pulse speed detected by the pulse generation speed detection means 12, and 14 is a drive direction setting means 7, a drive amount setting means 8, and a drive speed setting means. A drive source control means controls the applied current, voltage, pulse period, etc. to the drive source 4 according to the setting values set at 13, and 15 controls the drive source control means when a pulse signal is not generated from the pulse generation means 6 even after a predetermined period of time has elapsed. Immediate stop means resets the drive amount setting means 10 to set the set value to zero and generates a signal to stop the drive source 4; reference numeral 16 sets the drive amount when the drive direction detected by the drive direction detection means 7 changes; This is immediate inverting means for returning the set value in the means 10 to zero and generating a signal for driving the drive source 4 in the opposite direction.

In the drive amount setting means 10, the set value is sequentially subtracted by the number of pulses generated from the second pulse generating means 11, and when the set value becomes zero, the drive source 4 is stopped by the drive source control means 14.

The drive amount setting in the drive amount setting means 10 is performed according to the detection value of the focus ring rotation amount detection means 8, but the drive amount setting is controlled by the output of the immediate stop means 15 and the output of the immediate reversal means 16. , the drive source 4 is immediately stopped and reversed.

The instant reversal means 16 causes the drive amount setting value in the drive amount setting means 10 to be set to zero only when the detection value in the focus ring rotation direction detection means 7 and the setting value in the drive direction setting means 9 are different within a predetermined time ( It has the function of temporarily stopping the drive source 4.

In FIG. 2, a block A surrounded by a dashed line corresponds to the power focus device 100 shown in FIG. 1, and the block A includes the manual focus calculation circuit 2 shown in FIG. A configuration corresponding to circuit 5 is included.

In addition, in FIG. 2, dotted lines, dashed-dotted lines, and double solid lines indicate mechanical connections.

FIG. 3 is a diagram showing an example of an actual electrical configuration for realizing the control system shown in FIG. 2. In the same figure, 30 is M
PU (i.e. microprocessor unit),
31 is a counter, 32 is a reset circuit, 33 is a D/A
Converter, 34 is a voltage follower, 35 to 38 are drive sources 4 (
IIA is a pulse generation switch constituting the second pulse generation means 11 shown in FIG. Two pieces of No! that make up the generation means 6! This is a pulse generation switch. In addition, in FIG. 3, R represents resistance, and dotted lines represent mechanical connections.

The function of block B surrounded by a two-dot chain line in Fig. 2 is the MPU
30, a counter 31, and a reset circuit 32. On the other hand, the functions corresponding to the drive source control means 14 in FIG. 2 and the drive control circuit 5 in FIG.
It is implemented with a configuration consisting of a part of the PU 30, a D/A converter 33, a voltage follower 34, and transistors 35 to 38.

FIGS. 4 and 5 show an embodiment of the pulse generating switches 6A and 6B and the pulse generating switch 11A shown in FIG. 3. In FIG.

In FIG. 4, numeral 39 is the first helicoid tube of the camera lens barrel (or the lens barrel of an interchangeable lens), and the first helicoid tube 39 is supported by the lens barrel body etc. so that it can only rotate. It has become.

A lens 3 attached to a second helicoid tube (not shown) (supported so as to be rotatable and movable in the optical axis direction with respect to the lens barrel body) is accommodated at the inner diameter position of the first helicoid tube 39. Due to the screw engagement between the first helicoid tube 39 and the second helicoid tube, the lens 3 moves along the axial direction relative to the first helicoid tube 39 when the first helicoid tube 39 rotates. It is now possible to do so. Teeth 39m are formed on the outer peripheral surface of the first helicoid tube 39, and the first helicoid tube itself is configured as a ring gear.

A gear train 40 for rotating the first helicoid cylinder 39 by meshing with the teeth 39m of the first helicoid cylinder 39 is disposed outside the first helicoid cylinder 39.
0, rotation is transmitted from the drive source 4 disposed outside the first helicoid cylinder 39.

The focus ring 1 shown in FIG.
A ring 41 is fitted on the first helicoid tube 39 so as to be relatively rotatable on the outside of the helicoid tube 39, and rotates integrally with the focus ring 1. A conductor pattern 42 is formed on the outer peripheral surface of the ring 41 as shown in FIGS. 4 and 5, and the four conductor turns 42 are grounded as shown in FIG. Conductor 9
The turn 42 has two pattern portions 42 and 42 aligned along the circumferential direction of the ring 41 and shifted by a half pitch from each other.
b is formed. On the outside of the outer circumferential surface of the ring 41, there are two sliding contact pieces 43 and 44 of two 9-lux generating switches 6 and 6B that are supported in a stationary state by a support member (not shown) (fixed tube of the lens barrel body). The contact piece 43 of the /4 pulse generation switch 6A is positioned to contact the pattern portion 42a, and the contact piece 44 of the pulse generation switch 6B is positioned to contact the /4 turn portion 42b.

Therefore, when the ring 41 is rotated in the direction of arrow f in FIG. 5, the circuit connected to the two contact pieces 43 and 44 receives pulse signals whose phases are shifted by half a pitch from each other as shown in FIG. will occur. 5 and 6, when the contact pieces 43 and 44 are on the line a in FIG. 5, the pulse signal P1 generated in the pulse generating switches 6A and 6B is
The voltage of P and P becomes the value on the a line in FIG. 6, and the contact piece 43
and 44 are on the line b in FIG. 5, the voltage of the pulse signal generated by the noise generating switch 6 and 6BK becomes the value on the line b in FIG.

Both! Since the pulse signals P and P are different in phase by half a pitch, the rotation direction of the ring 41 can be detected by comparing the number of pulses or the phase of both pulse signals within a predetermined time.

On the other hand, as shown in FIG.
5 is formed, and the conductor/four turns 45 are also grounded like the conductor and turns 42. A pulse generating switch IIA having a contact piece 46 in contact with the conductor/arm turn 45 is provided outside the first helicoid cylinder 39. Since only one type of pulse signal is generated from this /4 pulse generating switch 11A, this pulse signal represents the amount of rotation of the first helicoid cylinder 39 (that is, the amount of movement of the lens 3), but the direction of rotation is determined by the pulse signal. It cannot be detected from the signal.

Next, first, with reference mainly to FIG.
The operation of the Wharf Orcus device will be explained.

The photographer first rotates the focus ring 1 in the first direction with his or her finger, and as a result, the ring 41 (see FIG. 4), which is integrated with the focus ring 1, rotates in the direction of the arrow f1 in FIG. 5, for example. Suppose that As a result, the two pulse generating switches 6A and 6B (Fig. 4) constituting the first pulse generating means 6 (Fig. 2) generate two types of pulses having different phases as shown in Fig. 6.・f pulse signals P1 and P2
This pulse signal is applied to the focus ring rotation direction detection means 7, the focus ring rotation amount detection means 8, and the pulse generation speed detection means 12, respectively, and is also applied to the immediate stop means 15 at the same time. As a result, the focus ring rotation direction detection means 7 detects the rotation direction of the focus ring 1 by comparing the number of pulses of the two types of pulse signals P1 and P2, and the focus ring rotation amount detection means 8 detects the rotation amount of the focus ring 10. is detected.

On the other hand, the pulse generation speed detection means 12 detects the rotation speed of the focus ring 1.

Further, since the pulse signal is also applied to the immediate stop means 15 that supports the timer circuit, the operation of the timer circuit within the instant stop means 15 is started.

Note that in the actual configuration shown in FIG. 3, the focus ring rotation direction detection means 7, the focus ring rotation amount detection means 8, the pulse generation speed detection means 12, the immediate stop means 15, etc. are all implemented in various registers and in the MPU 30. It is composed of a built-in timer and a counter 31.

As described above, when values such as the focus ring rotation direction, focus ring rotation amount, and pulse generation speed are detected from the pulse signal generated by the rotational operation of the focus ring 1, the drive direction setting means 9 sets the drive source 4. In addition, the drive amount of the drive source 4 is set in the drive amount setting means 10, and the drive speed of the drive source 4 is set in the drive speed setting means 13. Signals representing these set values are applied to the drive source control means 14, and the drive source control means 14 drives the drive source 4 based on these set values.

On the other hand, when the rotational direction of the focus ring 1 is detected by the focus ring rotational direction detection means 7, an input corresponding to the rotational direction is also input to the immediate reversal means 16 by the output of the detection means 7.

In this case, since the same direction as the detection direction in the detection means 7 is set for the drive direction setting means 9 by the detection means 7, the output of the drive direction setting means 9 and the detection means 7
The instantaneous reversing means 16 to which the output is applied does not produce an output that makes the set value in the drive amount setting means 10 zero.

When the drive source 4 is driven, the rotation of the drive source 4 is transmitted through the gear train 40 to the first helicoid cylinder 39 at a reduced speed in FIG. 4, and the first helicoid cylinder 39 is rotated. 1st
When the helicoid tube 39 is rotated, the first helicoid tube 3
A second helicoid tube (not shown) in a screwed relationship with 9 moves in the axial direction, and the lens 3 becomes, for example, the first helicoid tube 39.
The comb is ejected toward the tip. Also, when the first helicoid tube 39 rotates, the conductor formed on the outer circumferential surface of the first helicoid tube 39! Since the turn 45 moves in the circumferential direction, the rotation amount of the first helicoid tube 39 (that is, the amount of movement of the lens 3) is controlled by the pulse generation switch IIA, which has a contact piece 46 that contacts the conductor nine turn 45. A 1,000 lux signal representing the drive amount setting means 1 is generated, and this .f lus signal
It is fed back to 0. The driving amount setting means 10 is the second
The initial setting value (i.e.,
The initial setting drive amount based on the detection value detected by the focus ring rotation amount detection means 8 is sequentially subtracted, and when the initial setting value becomes zero, the drive source control means 14 stops the drive source 4.

When the focus ring 1 is first rotated in the forward direction and then rotated in the reverse direction, the pulse signal P is generated from the pulse generation switches 6A and 6B.

The phase of P2 and P2 is also reversed, and the focus ring rotation direction detection means 7 generates an output signal of, for example, +1 as the rotation direction when the focus ring 1 rotates in the forward direction. An output signal of Therefore, the immediate reversing means 16 receives a -1 input signal from the focus ring rotation direction detection means 7, and also receives a +1 input signal from the drive direction setting means 9 during the previous focus ring operation. ,
The immediate reversing means 16 outputs a signal that makes the set amount in the drive amount setting means 10 zero. As a result, the set amount in the drive amount setting means 10 becomes zero, and the driving of the drive source 4 is immediately stopped by the drive source control means 14. Thereafter, the drive is immediately started based on the newly set drive direction and drive amount. is started and the drive source 4 is reversed.

On the other hand, when the focus ring 1 is rotated, the first pulse signal is generated from the pulse generating means 6, and while the driving source 4 and the lens 3 are being driven in accordance with the pulse signal, from the time when the first pulse is generated. If a subsequent pulse is not generated even after a predetermined period of time has elapsed, the timer circuit in the immediate stop means 15 times up, and the drive amount setting means 1 is
A signal is generated to set the set value of 0 to zero, and as a result, the set value of the drive amount setting means 10 is set to zero, and the drive source 4 is immediately stopped. Therefore, the drive source 4 does not rotate for a relatively long time after the rotation operation of the focus ring is stopped (the drive source 4 immediately follows the operation of the focus ring l).

Figure 7 shows MPU 3 in the actual device shown in Figure 3.
1 is a flowchart of a program that operates 0.

The operation of the apparatus shown in FIG. 3 will be explained below with reference to FIGS. 3 and 7.

When a power supply (not shown) or a stain source is turned on, the reset circuit 32 is activated.
outputs a low level signal for a certain period of time and resets the MPU 30. Thereafter, the reset circuit rises to a high level, and the Q MPU 30 starts executing programs in order from (1) below.

(1) 1 (high level) from output port P20 to P23
Output. As a result, the transistors 37 and 35 are turned off, and the transistors 38 and 36 are turned on, thereby lowering both ends of the motor 4 to ground and applying a dynamic brake.

(Set the timer TIMER in 21MPU to O.

The timer TIMER has a function of incrementing the value by 1 at regular intervals.

+3) V Sister MP, MDIR, EDIR,
Clear 0LDSW.

MP, EP, MDIR, EDIR, 0LDSW
It'i is a register in MPU 1.

(4) Output 1 to port P24 and clear the value of counter 31.

(5) Wait for a while while the value of the counter 31 is reset.

(6) Output O to port P24 and return the counter 31 to a countable state.

(7) Read the contents of the counter 31 from the port PORTO and store it in the register EP.

Switch 6A unless the focus ring is rotated.
, 6B do not change, so the value of the counter 31 remains cleared at (4), so EP is set to O. (8)
-Q(I is (4)) - Clears the value of the counter 31 similarly to (6).

Determine αυ EP=Q, and now EP=O, so branch to +35.

(To) 7. Put 0 in the one-way ring rotation direction register EDIR.

Determine the value of C24 motor rotation direction register MDIH,
Since it is cleared to O in (3), the process branches to Qη.

C7) Clear registers MDIR and MP.

(To) Apply the brake to motor 4 in the same way as in (1).

Then return to (7).

Therefore, while the focus ring does not rotate, (car (8) - (9) - (11 - αυ - (to) - (to)
-@-(37)-(to) is executed repeatedly. During this time, the motor 4 maintains the brake state.

Now, if you rotate the focus link in this state,
Switches 6A and 6B are turned on and off to produce a signal P as shown in FIG.
, , P are generated, and each time the switches 6A and 6B are turned on, the signals P□ and P2 become high level, so the counter 31
The value of is incremented. Therefore, the EPQ value input in (7) becomes positive. - When the value of the degree counter 31 is read, it is reset to 01 from (8), so that it is not read twice.

EP=O is determined at αυ, and since they are not equal, the process branches to C2.

Determine αZ EP>O and branch to C3.

(13 Focus ring rotation direction register EDIR +
Store 1.

(1E9 Outputs EP/T IMER from output port 3 to D/A converter 33. The amount of pulse per unit time divided by the time it takes to change the arm pulse of the focus ring) A voltage proportional to will be applied to the output of the voltage follower 34.

aη Determine the value of register MDIH, and since it is cleared in (3), branch to (c).

The amount of motor movement is determined and the EPO value is stored in the register field.

Soter rotation direction register MDIR to EDIR
Stores the O value.

C24) Determine the value of MDIR, and since it is not 0, branch to the device.

Determine the value of field 6. Since it is not 0, go to (c) fi MDI
Determine the value of R, since it is +1, go to (5) @ P2O, P2
By outputting O to 1, outputting 1 to P22 and P23, turning on the transistor 38.35 and turning off the transistor 37.36, current flows from the voltage follower 34 to the transistor 35, the motor 4, and the transistor 38. is driven to move the photographing lens 3 toward the infinity end.

(c) Determine the state of switch IIA, if it is currently on, go to (to) (to) Set register 0LDSW to 0 and return to (7).

If you do not rotate the focus ring, the counter 31 will remain at 0 (7) - (8) - (9)
-(II-〇υ-(to)-(to)-C24)-4-(to)-Kanichi(to)-(to) is repeated.

Eventually, the photographing lens 3 will move to the desired position by the drive of the motor 4, and the switch IIA will be in the OFF state.
).

G1) Determine the status of register 0LDSW. Since it is set to 0 in ■, the value of c3z MP to C33 is decremented.

(To) Set 0LDSW to 1.

After that, at the branch of Gυ, it does not go to Oa but to Q.

(7) -(8) -(9) -(IG -(11)
-C (St -CIG -C!4) -125-C6)
The loop of -(5)-Gυ-(b) is repeated while switch IIA is off.

Therefore, in the routine from (b), switch IIA
The value of the register MP is subtracted by 1 each time the signal rises from on to off.

If the above loop is executed, MP will eventually become 0 (
At (to), branch to (b) and apply the brake to motor 4.

In this way, the photographing lens 3 can be electrically driven by an amount equal to the rotation pulse of the focus ring.

Next, the case where the focus ring continues to be rotated while the motor is being driven will be explained.

Before changing from the brake state to the energized state,
α3- Q'3-(l[9-α Ku(sha)-U-el
It is the same as the loop '4)-■-(to)-(to), but
Since the focus ring is turned when reading the value of counter 3 for the second time, a positive value is set to EP. α21
- (13) - (16) are controlled in the same way as the previous time, and branch to mark a at α.

08 Compare the values of the focus ring rotation direction register EDIR and the motor rotation direction register MDIH, and if they are in the same direction, branch to the lens.

Add the newly increased pulse EP to the C9 motor movement pulse register MP.

Since the control is thereafter performed in the same manner as described above, the photographing lens can be moved in accordance with the amount of rotation of the focus ring that continues to be moved.

If the focus ring is turned in the opposite direction, the value of the counter 31 becomes negative, so the process branches to 14 at αa.

α 滲 Focus ring rotation direction register EDIH -
Set to 1 to indicate reversal.

Convert the value of C9EP to an absolute value.

Thereafter, the control from αe to (c) is performed in the same manner as during normal rotation.

Since MDIR is set to -1 in (b), (
to).

(c) Port P20. 1 on P21. P22. Outputs O to P23. Therefore, current flows from the voltage follower 34 to the transistor 37, motor 4, and transistor 36, moving the photographing lens 3 toward the near end. Thereafter, the reverse direction can also be controlled in exactly the same manner.

Next, a case will be described in which the focus ring is reversed while the motor 4 is being driven. When the focus ring is reversed, it will feel very unnatural if the motor 4 does not follow the driving direction.

When the focus ring is reversed, the value of the counter 31 at -14 and the sign of EP are reversed.

Therefore, (in 1 second, the registers MDIR and EDIR become no longer equal, and the process branches to step 2).

■ Discard the previous value of the lens movement amount register MP and set it to the value of EP.

I21) Change the rotation direction of motor 4 to a new direction.

In this way, 40 rotations of the motor can also be reversed in response to the reverse rotation of the focus ring.

It also feels unnatural that the motor continues to run for a while even after the rotation of the 7 Orcus Ring is stopped. Therefore, if the value of the counter 31 remains 0 for a certain period of time T after the timer TIMER is set to O in (2) or αG, it is determined that the timeout has occurred (to) and C37
) and brakes motor 4, it is possible to bring the sense of focus closer to that of conventional manual focusing.

In the above embodiment, the rotation of the focus ring is linked to the rotation operation of the focus ring. The first pulse generating means that generates a pulse signal and the second pulse generating means that generates a pulse signal in conjunction with the rotation of the first helicoid cylinder are constructed as sliding contact type switch means.・Photoelectric type f-lux generation means,
It goes without saying that it may be constructed with a magnetically sensitive type, capacitance type, or other type of non-contact saturable converter. Further, as the drive source 4, not only a known electric motor but also an actuator whose rotation or movement can be controlled electrically can be used.

〔Effect of the invention〕

The power focus device of the present invention shown in the above embodiments is easy to use because it uses the same rotary operation type focus ring as the conventional manual focus device as the manual focus operation member. (11) Reversal of the focus ring The lens drive source immediately follows when the focus ring is rotated or the operation is stopped. You can obtain the following effects.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing a schematic configuration of a camera or an interchangeable lens equipped with a 4-wharf orcus device and an auto-7 orcus device of the present invention, and Fig. 2 shows a control system of an embodiment of the power focus device of the present invention. FIG. 3 is a block diagram showing an example of the actual electrical configuration of the embodiment shown in FIG. 2, and FIG. FIG. 5 is a perspective view showing an example of a pulse generating means and an example of a lens drive mechanism related to the focus ring and the first helicoid tube; FIG. 5 is a plan view of one of the pulse generating means shown in FIG. 4; This figure shows the phase and waveform of a pulse signal generated in the pulse generating means shown in FIG. 5, and FIG. 7 is a flowchart for explaining the operation of the MPU 30 shown in FIG. 3. l...7 Orcus ring 2...Manual focus calculation circuit 3...Lens 4...Lens drive source 5...Drive control circuit 6...First pulse generating means 6A and 6B... /f pulse generation switch 7...Focus ring rotation direction detection means 8...Focus ring rotation amount detection means 9...Drive direction setting means 10...
・Drive amount setting means 11...Second) arm pulse generation means 11A...Pulse generation switch 1 2...Pulse generation speed detection means 1 3...Drive speed setting means] 4...Drive source Control means 15 River immediate stop means 16.
... Immediate reversal means 30..., MPU31... Counter 32... Reset circuit 33... D/A
Converter 34...Voltage follower 35-38...
Transistor 39...First helicoid tube 40...Gear train 41...Ring 42.4
5...Conductor no-turn 43.44.46...Sliding contact piece Figure 1

Claims (1)

[Claims] A focus ring that is rotated by hand, a lens drive drive source that drives a focusing lens, a pulse generating means that is linked to the rotation of the focus ring and generates a pulse signal according to a rotation angle, and the pulse signal focus ring rotation direction detection means for detecting the rotation direction of the focus ring from the pulse signal; focus ring rotation amount detection means for detecting the rotation amount of the focus ring from the pulse signal; drive direction setting means for setting the drive direction of the lens drive drive source based on the detection result of the focus ring rotation amount detection means; and drive amount setting for setting and storing the drive amount of the lens drive drive source based on the detection result of the focus ring rotation amount detection means. means, a drive source control means for controlling the lens drive source according to the drive direction set by the drive direction setting means and the drive amount set by the drive amount setting means; When the operation of the focus ring is stopped, a timer circuit detects the time during which the pulse signal is not generated, and when the timer circuit detects that the pulse signal is not generated for a set time or longer, the lens drive source is turned off. A power focus device comprising: an immediate stop means for immediately stopping the power focus device.