JPS5949522A - Automatic focusing device - Google Patents

Abstract

PURPOSE:To perform matching of the response speed and the damping characteristics of each lens, by constituting the device with plural photographic lenses and a camera body and driving a lens driving motor with a motor driving current which is changed in accordance with driving characteristics of photographic lenses. CONSTITUTION:The light transmitted through a photographic lens 1 is focused onto a sensor 2 constituted with a CCD or the like. The output of the sensor 2 is digitized by an A/D converter 3, and the deviation from the focus position is detected in an operating device 4 by a known method, and a control output corresponding to this deviation is transmitted to a driving circuit 6 by a controller 5. The photographic lens 1 is moved by a motor 7 which is driven by the driving circuit 6, and the extent of movement detected by a movement extent sensor 8 is fed back to the controller 5. The controller damps the lens when the feedback pulse and the output of the device 4 have a prescribed relation. The circuit 6, the motor 7, and the sensor 8 are provided in the lens structure body.

Description

DETAILED DESCRIPTION OF THE INVENTION [Misfire 81] is an automatic focusing device in a camera consisting of an algebraic photographing lens body and a camera body.

Conventionally, one driving method for a projection lens with a 0.110 focal length and a 43% Xi setting is to drive the lens at a high speed when the object is in a heat-containing state (if it is off the target), and In some cases, it has been proposed to move the photographing lens to the focusing position at a low speed to solve the conflicting problem of response speed and y (α shadow reflection damping and timing) during the time until focusing. Near this point, methods have been taken to lower the driving speed of the photographing lens drive motor, such as lowering the driving pressure of the photographing lens drive motor, or driving the motor intermittently using pulses.

A specific example of the latter can be found in the embodiments of Japanese Patent Laid-Open No. 57-46216 by the present applicant. There is also a method in which the shadow lens is moved to the in-focus position (1'α) by moving a motor for moving the shadow lens based on the amount of deviation of the image plane by the photographing lens from the focal point. However, in these methods, the gear ratio of the transmission gear used to drive the photographic lens, the friction generated along the way, and the
Since it does not take into account the differences in the weight and dipping moment, etc., the Pjs Luli circuit is compensated using the same drive box and press drive pulse as described in @. Also, the speed and characteristics differ depending on the lens. However, there was a drawback that the 6-shade lenses had different tJ values, and the power method could not be obtained for each projection lens used.

For example, if the moving speed of the shadow lens is too fast, there is a risk that the braking will be insufficient even with the brake, and the in-focus point may be missed. Brake ffi:l %i) Insufficient force1. It also means that the hunting will be soaked in the Q match. On the other hand, when the lens is moved 1g (11J) to 1), it is too low and 1) focuses. Deteriorate.

The present invention solves these drawbacks by improving the photographic lens.
'j j'7! ] QMotor F changed according to characteristics
]A By dispatching the motor for moving the photographing lens with a dynamic current, the response speed of each (,: +1. shadow lens, one body) I) shadow lens and ? i1. l approx. 1. The purpose is to layer the device so that it becomes a moving tube.

Hereinafter, the actual*li pH of the present invention will be explained with reference to the drawings.

FIG. 1 is an overall diagram of the servo system of the first embodiment of the id, ftaJ, , f3-moon device, and each function is represented by blocks. p), the outline of its operation is explained below.

After passing through the photographing lens 1 in the photographic lens body, an automatic focusing device (not shown) is placed on the sensor 2, which has passed through the academic system and has been layered by COD, etc. Sensor 2 A/D detects the cigarette by making one pixel per pixel.
Output to converter 3.

A/D lj t; c! ;it, fi each;(,
Output ij? 3(:i', γ:;・:j li:Q-4
L is inserted and (, i, > how far j(() is from the useful position f'L to the shadow lens 1 is expressed by known means. The result is The first and second sister 5 is outputted to 1r: Based on this, the flio output is outputted to the full output driving circuit 6, and the 1st and 1st half of the lens 1 is outputted to the mature position ``J'' to ``J''.
i<g:I). (The hourglass-shaped lens 1 is moved to the focusing position by the drive motor 7, but (the amount of movement of the I°1λ shadow lens 1 is
is detected and fed back to the assisting device 5. The group 7'7b quantity sensor 8 is connected to a generator 88, a receiver 8b, and a rotary plate 8c between them. , along the outer circumference, a slit-like ``I'',; Is this movement?・[With the rotation of the ζ holder I,
This time 1: “ji: The number of barsui 1 according to I.3゛
;If the number is lost to the first page, it is sent to the control device fi'f:5. The pulse of ζ- (;-4 is called the feedback pulse signal.

Similarly, the number of pulses of this foot hack pulse No. 414 d corresponds to the rotation 1i of the motor and the movement angle λ of the photographing lens, so it ultimately corresponds to the amount of movement of the subject image due to the movement of the photographic lens. There is.

When the control device 1-5 detects that the above-mentioned calculation result and the number of feedback pulses have a predetermined relationship, it outputs ff+lJ control output to the body ■/υ circuit 6 so that the brake is applied to the motor 7. Then, after a certain period of time, the brake metal is released and the servo is finished.

This fixed time is the time necessary for the motor to stop reliably by the brake. - When the servo cycle is completed, the same operation is repeated from the first distance measurement operation.

Similarly, in this embodiment with the above configuration, device 2\3.4.5
are arranged in the camera body, and the four arms 6.7.8a, 8b, 8c and the photographing lens 1 are respectively arranged in the replaceable photographing lens 4'4.

FIG. 2 shows a specific example of the configuration of the control circuit.

The arithmetic coloring 4 determines the front and rear focus, and outputs the image plane deviation f'1 (actual subject 1 image position t1!'' and the planned position (deviation from two points before) to the latch circuit 51 (G output).Circuit 51 sends the ρ plane deviation n signal to the digital comparator 52.53, and after l''11J sends the pin signal (signal to rotate the motor forward or 1j: reverse) to the OIL gate 54.55.Specifically, As the 61J bin No. 3, the L level and H level are applied to the gates 54 and 55, respectively, and as the rear bin signal, the gates 54.
II level and L level signals are sent to 55, respectively. When the constraint 1 is set to [G], the counter 56 counts the feedback pulses from the ψ event T. The number of pulses of this feedback pulse signal represents the shift of the subject image by the photographing lens as the torsion lens moves (hereinafter referred to as image plane 8tII length). Compare the deviation R (number 0 and the signal 1 of the counter 56)?1, and calculate this (, f22 and deviation 1 (...) When the count value, i.e., the value of the signal 1 of the counter 56, approaches the predetermined value, i.e. Image plane shift amount and 19th plane fi) F・j
When the difference from 9 becomes r) 1 quantity, the operation lens 1 changes the I level before the tray (' (assuming that the D of 7-1a can be moved by 1υ to the constant neighborhood), and outputs the output to the NΔMD gate 57. Output to.

When the digital comparator 52 outputs the I-th novel output to the NAND gate 57, the pulse output of the pulse generator 58 is inverted through the NAND gate 57 and ORed.
Join Gate 59.

On the other hand, when the count value of the counter 56, that is, the amount of image plane movement matches the image plane deviation i (Δ), the digital comparator 53 detects this and assumes that the photographic lens has reached the thermal position a.
Outputs I level output. This is OR gate 54.55
．． 59 and triggers the monostable multi 60. The monostable multi 60 outputs the 4M signal which becomes L level only during the braking time C to the AND gates 61 and 62, and the AND gates 61 and 62 are further provided with OR gates 5 and 5, respectively.
4.59, the output of OR gate 55.59 is input.

Because of the above, the output of the digital comparator 53 is at L level in the vicinity of the in-focus point, so the OR gate 54
．． Reference numeral 55 indicates the pin after J; the pin after J actually outputs I level, L level, and TI level, respectively, while the output of digital comparator 52 is L level, so both NAND gate 57 and OR gate 59 output II level. However, the monostable multi 60 also outputs H level.

Therefore, the outputs of the OR gates 54 and 55 are directly output to the terminals T2 and T3.

Next, in the vicinity of the focal point, a pulse output is output from the NAND gate 57 to the OR gate 59 as described above, and since the output of the digital comparator 53 is at the L level, (JR gate 59id: this pulse '1AND Inform the gates 61 and 62.Also, immediately stabilize the machine/
1. :f6(l outputs H level, OR gate 54
．． For 55, depending on the front and rear pins, either one is H level!・Since full output is being generated, A is manually producing this H level output.
N I) A pulse is output from either gate 61 or 62. (l[Then, this period of JuJ becomes a pulse motion.

When the focus is finally focused, the output LH of the digital comparator 53
Therefore, the outputs of OR gates 54, 55, and 59 are all 1 level. Therefore, the brake pulse (L level) immediately after focusing changes from monostable multi 60 to AN
The li L level is applied to the terminals T2, T, and the brake is applied only during the period when it is applied to the D gates 61 and 62, but after that, the monostable multi 60 outputs the II level output and the terminal T! , TI both become 1 (level) and the servo ends.

The above situation is shown in No. 4 of Figure 3.

FIG. 4 is a specific example of a drive circuit 6- that uses #y, the control signal from the control device 5 shown in FIG. A photographic lens equipped with a camera is provided at the 1st and 6th positions. The operation will be explained below.

Terminals T2 and T3 are input terminals for control signals from the control device 5 of FIG. Here is 匍U @! ] The signal shall be Digital No. 414, which can be controlled manually, and the 7 level shall correspond to OV (GND), and the H level shall correspond to a voltage of vCC + BE or more (VaE is the voltage between the base and emitter of the transistor). Approximately 0.C3V, V at normal potential
cc is the 11L source voltage).

Apply the operating mode to the control terminals T2, T, -,! Each type of unpacking 1 signal will be explained.

()) When II level control cap No. 4g is applied to both terminals T and T, □ (standby state)! 'NP) The transistors Q+, Qt and Q7, Qa have resistors R,, R, SR, and Rn at their bases. R
7. Since the II level voltage is applied by valve Rs, everything becomes OFF'. Therefore, the PNs forming the bridge
P) Transistors Q3, C20, and NPN transistors Q4, Qn'1 whose bases are connected to the flippers of transistors Q7, Q2 through resistors R5, R4k, respectively.
) The remoter MKij is OFF and is stationary without being supplied with power. In this case, all of the transistors at times W'it are O
It is an FF, the current consumption of the circuit is 0, and it is in a servo standby state.

(li) RiA + child T21cL level and 9iA
When f child T B 4CIl and △8le's li:1 suppression signal is applied □ (positive direction [i41 transfer parent DilJ) resistor R1 is valved and 1. is applied to the base of transistor Q2. :I
, mud is supplied and the transistor νQ is turned on. Thereby p-transistors Q3 and Q.

is turned ON, so a current flows to the motor 81 in the direction of the arrow Δ and is applied to the morph M metal L1. On the other hand, transistor Q,
Since Qa is OFF, transistors Q4 and Q5 are 0.
FFI is here. Also, at this time, transistor Q is turned on, but since transistors Qa and Q7 are turned off, there is no effect on the operation of the circuit.

(11) When a control signal of II level is applied to terminal T and L level control signal is applied to terminal T3 (reverse direction rotation) The circuit operation is opposite to the case of (11), and transistor Q
4, Qs, 9th transistor, Qa is ON, all other transistors are OFF, fx, l), in the direction of arrow B, that is, (11
), the motor SS dynamic current flows in the opposite direction, and the motor M
is driven to rotate in the opposite direction to that in case (11).

(1) When fcL level control signals are applied to both terminals T and T, (brake operation, transistors Q and Q are turned on, but at the same time transistors Q and Qa are also turned off.
Therefore, the emitter current of transistor Q7 is supplied from transistor Q1, and the emitter current of transistor Q is supplied from transistor Q. Also, the vcsp sum voltage of transistors Ql and Qs is
Since p is smaller than ■nx required to turn on , and Q, transistors Q3 and Q5 are 0FFL, and transistor Q4
Only Qa is ONi. The loop consisting of transistors Q4 and Qa and motor M is)1. ! The action of applying a brake to the motor M during one movement is 77. This is because after the motor drive rJJJ current is cut off, the motor M, which is rotating due to inertia, temporarily becomes a generator and sends a current through the short circuit loop, and the rotational energy is released as thermal energy, and a brake is applied to the rotation of the motor M. It takes. Due to the rotation of the motor Δ1, one of the transistors Q4 and Qa operates in a reverse transistor mode (the roles of the emitter and collector are reversed, and current flows from the emitter to the collector in the case of a p, NPN transistor). .

On the other hand, a light emitting diode LED and a phototransistor Q
10 are the emitter 8a and the light receiver 8b in FIG. 1, respectively?
:Configure.

If the terminals T, , T, are small (and one is at the L level), the mode base of (Iψ is the resistance R
, and to the terminal T3 via the diode D3, and to the terminal T via the resistor R0 and the diode D4, since the transistor Q<l is 0N-j, a current starts to flow through the resistor R10. emits light. Therefore, while the motor is being driven, the amount of movement of the photographing lens 1 is detected by the diode LED and the photointerrupter formed by the phototransistor Q+o, and the resistance R1
A feedback pulse signal appears at the terminal T, which is connected to ground via 1. This terminal T is the control device 5
This is an output terminal that sends out a back pulse signal.

The static control mode is explained below, but if the photographing lens is within the vicinity of the in-focus position, it is necessary to reduce the driving speed of the first lens to improve braking at the in-focus point. , Ifυ's mo 13 is as follows.

I will explain all of this using the time chart shown in Figure 3. In the figure, the period t is the static mode (11) described in 13tf, and the period i, t
GID"'cl t:t Reiko'r t,'r 11
(7) When the motor is at full speed, one is at TI level and the other is at L level. Ji-turn. However, in the vicinity of the focal point;
When the 5'li fortress 5 detects from the count number of feedback pulses, the control becomes the pulse driving mode b indicated by the period t. That is, one of the terminals T and 1 and 3 remains at the L level, while the other one periodically returns to the II level and then to the L level. Therefore, when this other terminal is at L level, the brake is applied to the motor Ji[kap, and when this other terminal is at H level, the motor is driven. In other words, the static mode (:) and (IVJ) described above are repeated alternately, so the motor energization time is (
11) and (Hi), the lens driving speed is t! period. When the photographic lens is driven to the in-focus point, the terminal T! The application of L level No. 3 to \T3 continues for a braking period t3, and the motor suddenly stops under braking. 1. ．． 1. , ts, the control power on one side is at the L level, so the projection lens is driven by the light emitting diode (LED), and the feedback pulse is guaranteed to be generated (during ts, the motor is stopped). Since it is, there is no meaning in depth).

In the above explanation of the dynamic drive mode t, the pumping speed of the motor was achieved by returning the motion to the brake and fat in a pulsed manner, but the pumping speed was achieved without using the brake sound (6 corpses 1: 1). There is also a method of repeating pauses in pulses.

When C &, J one control 1 manual t'', tINFO between I
I level, L level between u and t, and pulse during t2. In this case as well, the motes (1) and (11) and (ijjl') described in 1.

is ON and OFF during t2, which hinders the generation of feedback pulses, so by adding an appropriate timer circuit, the light emitting diode ζIi ED + is ON during t.
There is a necessity to keep 'i'. Here, the following explanation will be given by taking the ff1lJ invitation signal as shown in No. 3 and 1 as an example. Also, the duty of the pulse during t2 is 50
%.

J, 1. As shown above, use a lens with a relatively short focal length. The single-acting circuit 6 shown in Fig. 4 installed inside the lens damage body generates pulses. l JL! The control signal during period J is a pulse with a duty of 450% issued from the pulse generator 58 in FIG. 2, which is used as it is to control the motor. However, the drive characteristics of the projection lens are different. 7, the motor 'c jet l+b L/' is controlled by the same control input as shown in Fig. 3, but the Ii control characteristic of the imaging lens is different and is < 2+, so a control force method is used to compensate for this. I need to think about it. For this reason, the t! The duty ratio of the drive pulse is
In lens drive 1 and 1 path, change according to the driving 'tf characteristics of the lens used, and set the lens displacement speed near the hot spot, more precisely, the image plane of the image formation plane, and the excitation degree to an appropriate degree. There are ways to make it so that the Generally speaking, it is possible to raise or lower the duty of the pulse at t, but in this C, we consider a lens structure with a large lens such as a long focal length lens, and use the Jυ palm brake to control the fetal movement time at t2. Try to reduce the time. This iJ: In large lenses such as long focal length lenses, generally 4'A'< mechanical load is large, so tl is continuous;
This is because the speed decreases significantly with 0% duty pulse driving.

Fifth and first, it includes the function of changing the duty of the human caballus, and the large lens f: has a lens H'>.

The circuit in Figure 5 has six components, which is the circuit in Figure 4 with the addition of a circuit for changing the duty of the pulse (the part surrounded by @! in the diagram). Same as the time chart in Figure 6. When the terminal ゛r goes from the L level to the H level, the transistor Q11 immediately turns O.
N and discharges the capacitor C3 at once, so the resistor RI3 is connected to the collector of the transistor Q17 and the transistor Qu, and the base becomes the resistor RIll% R14.
A transistor Q+sl whose emitter is connected via
d As shown by the lower line in Figure 6, kV OF F (!:
lx le. '1 Iode D, i and terminal T.

II level human power is VCC +V7J (Dio-1
:'s interrogation "tfi; Make sure the pressure does not rise above 9&11'
This clamps the higher than necessary H level voltage at terminal T, and when an H level is applied to terminal T2, capacitor C7 is reversely charged and transistor Q□ As shown by the line in Fig. 6, the base of the terminal is made to be higher than VCC (not higher than VCC). However, when the terminal T, (T,) is at H level, it is assumed that there is a signal resistance of an appropriate magnitude. .Next, terminal T,
When the voltage rises to the low level, the transistor Qll becomes 0FFL.
, diode D1, and capacitor CI through resistor R11.
begins to charge. The time when terminal T becomes L level is 1
=0, transistor Q1. The voltage at the base of VB
The result is as follows.

Vn=Vcc -exp () (where -C:1R
I2) 4 τ Here, ignoring the interpolation voltage of diode D, terminal Tt
The signal trace impedance was set to 0 when (Ts) was at l level.

As VB decreases with a time constant τ as shown by the line in the Fu6 diagram, the time comes to turn on the transistor Q+2e. If the base-emitter voltage required to turn on the transistor QIz is van, then the transistor Qll will turn on after t2o has elapsed by VCC 1o = τAn - ■cc-VBE
Then, transistor Q+5i is turned on.

Therefore, when the pulse signal Q is at t in FIG. 3, the time of the L level of the pulse (M number) from the control c1+ device α5 is extended to, and the time of the L level is shortened by 10. This situation is depicted in the upper gland and lower crane in Figure 6. The explanation so far has been made regarding the pulse input to the terminal T, but since the circuit is left-right symmetrical, the same applies to the pulse input to the terminal T3. Therefore, regarding the broken line portion on the right side of FIGS. 1 and 5, each element is only indicated by a reference numeral and the explanation thereof will be omitted. However, the time constant of pulse expansion on the terminal T1 side τ/ -C2・n
+y must be equal to C1·nap to eliminate differences in speed depending on the driving direction. Please note that due to the shape of the photographic lens body, the mechanical load on the motor depends on the direction of movement! ! 4, then this 'f: τ and τ' to compensate
can be changed. Oka, Figure 5 shows transistor Q.
+s, Q 14, connect terminals T2, T, in Fig. 4 to Fti
(If you think that I mean it, the OF of transistor Q +3 (-Q +4) will change due to the pulse duty change.
When the F time LO is extended and the motor moves 1) tJ becomes longer, the BL/-K time becomes shorter and the 6th
It can be seen that the average torque of the motor during +2 pulse &'s rXHQ in the figure increased.

Although the above explanation is based on the assumption that the flill 1 id in FIG. 3 is used, the pulse expansion circuit in the circuit in FIG. 5 operates in exactly the same way even with pulse driving without the above-mentioned 11 multiplication. Also, when the TL in Figure 3 is running at full speed or the TL is braking, the circuit in Figure 5 will ignore the slight time delay.
It operates in the same way as the 4 prisoner circuit. Therefore, if the I-movement circuit shown in Fig. 5 is used in a lens structure having a lens with a large mechanical load, such as a long focal length lens, and the number of time steps τ is determined according to the magnitude of the load, the It is possible to compensate for the fact that during pulse driving, there is significant confusion, the moving speed is slow, and the response of the servo is poor.

Although we have shown and explained the circuit that extends the period of the II level of the pulse based on the Jg Jokuku 5 figure, a circuit that shortens the period of ■ with a similar configuration can also be considered, and the pulse! When it is necessary to reduce the drive speed during j & potting, a groove can be used.

That is, as mentioned above (with single lens - C duty 50
% pulse drive, the mechanical load of the dynamic system on the lens calendar is sufficiently smaller than that of the standard lens (・u
For lenses with shadows (74 lenses), it is desirable to reduce the duty.In this way, the braking becomes insufficient and the lens does not overshoot the point or go back into hunting. Reduce.

By the way, switch SW in FIGS. 4 and 5 is a focus lock switch, and when switches S and w are turned on, the emitters of transistors Q1 and Q6 are connected to YiAt"J-T2 via diodes D I and Dte, respectively.
, T s and enters the brake mode, terminals T, ,
T,'s (the shooting number 1 is fixed regardless of the g number.

One implementation fI of the present invention is described above in accordance with FIGS. 1 to 546.
In this embodiment, a circuit for changing the power supply time of the lens 0 drive motor according to the working force of the photographing lens is included in the drive circuit provided on the 1 non-zero body side. Therefore, the control output of the ft1ll mounted on the camera body 11iQK can be made into the Asahi 411 regardless of the type of projection lens on the lens body side, and it is useful for converting the control length 18 into an IC 17 and υ unit. I'm in the cage.

By the way, in the above embodiment, the duty ratio was changed according to the movement of the photographing lens to the kite so that the responsiveness of the shadow lens and the 11) response of the shadow lens and 11) were made appropriate. ! ; A method of changing the voltage of the fi4IJ'cL flow may also be considered. In addition, an expansion or compression circuit is included in the lens body (in some cases, it is not included as in the example lens structure in Figure 4), and the motor private current is connected to the individual lens body side. I was changing it, but this 1~
An F= iQ with a function is installed on the camera body side, and the camera body side reads the scale of the photographing lens each time, and changes the motor current υ based on the drive characteristics on the camera body side. It is also conceivable to send the motor to the lens body side and reduce the motor by one control object.

Conversely, the control device can also be provided on the lens body side, and the pulse generating means included therein can generate the 'A Eb pulse even though the p, l^ drive characteristics of the photographing lens have already been read.

Furthermore, in the above embodiment, as the focusing adjustment state, the direction of deviation from the in-focus position, the 131-plane deviation eclipse, and whether the photographing lens is within or outside the near-field redundancy range of the focusing position are detected. Then, in the direction of the focusing position of the photographing lens within this
・Decelerate the 1st b speed compared to that outside the range (・
Then move the lens to the in-focus position 1) f, and then move the motor with the motor drive 1, which has been changed according to the lens movement, in the vicinity of 7y. The type of automatic focusing device for fc is not limited to this, but it can be any type that detects the focus with the camera body and drives the focusing lens of the interchangeable lens. As described above, according to the present invention, there may be 11 of each photographing lens.
Since the motor is driven with a motor current corresponding to the movement characteristics and the photographing lens is moved to the in-focus position at an appropriate speed, excellent responsiveness and braking characteristics of the photographic lens can be obtained. In this way, quick and reliable automatic focusing becomes possible.

[Brief explanation of the drawing]

FIG. 1 is a schematic overall diagram of an embodiment of the present invention; the second factor is a circuit diagram of a specific example of the control device in FIG. 1; FIG. 3 is a time chart of control signals applied to terminals of the control device; Figure 4 is the first
Figure 5 is a circuit diagram of a specific example of the drive circuit shown in Figure 5. Figure 6 is a circuit diagram of another specific example of the 9 circuit, and Figure 6 is a time chart [main parts Explanation of the symbols] 1...Photographing lens 5.6...Driving means 7...Motor Application Nippon Gengaku Kogyo Co., Ltd.

Claims (1)

[Claims] 1. (Detects the focus adjustment state of the photographic lens from the subject that has passed through the darkest lens, and based on this, drives the t motor to bring the photographic lens to the in-focus position. In a camera comprising a plurality of photographing lens assemblies and a camera body having different driving characteristics of the photographing lenses, which is equipped with an automatic goldfish moving device, the photographing lens moving motor is provided with a motor drive current that is changed in accordance with the driving characteristics of the photographing lenses. An automatic focusing device characterized by having a driving means for driving 2. In-focus!!ll!1-node state, the direction of deviation from the in-focus position and the range rjT in the vicinity of the in-focus position of the photographing lens. Detects whether the lens is inside or outside the range, and focuses the photographic lens by slowing down the driving speed of the photographing lens in the direction of the focusing position within the range compared to the driving speed in the direction of the focusing position outside the range. At the same time, when the photographing lens is within the predetermined vicinity range, the driving means drives the photographing lens moving motor with a dynamic current from the motor that is changed according to the driving characteristics of the photographing lens.4) An automatic focusing device according to claim 1. 3. The automatic focusing device according to claim 1 or FR 2, wherein the driving means operates the motor with a motor driving pulse whose duty ratio is changed according to the driving characteristics of the projection lens. 4. The driving means includes a pulse generating means that generates a constant motor drive pulse, and a pulse that receives the constant pulse and changes it according to the PAjJ)Q'f characteristic of the photographing lens. converting means and J from the pulse converting means.
! Motor i? which controls the energization of the motor by motion pulses? ilJ elevation means ([the automatic goldfish device listed in F in claim 2 or 3. and motor flilj
The control means is provided on the photographic lens 41 body.
'f' Aquarium No. 4 [Automatic focusing device described in 1.